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THE
ABC OF AVIATION

Captain Victor W. Page

Sig. R. C, A. S.

has been censored, and passed for pub-
lication, by The Chief Military Censor,
Washington, D. C.

'.V

NOTICE

The author of this book, Capt. Victor W.
Pag^, Sig. R. C, A. S., having been called to France
for service, had not the opportunity of reading
the proof pages of this book before its publi-
cation, and, therefore, could not make any neces-
sary corrections before its publication.

The Publishers will appreciate it if the reader
will, therefore, call to their attention any seem-
ing errors.

The Norman W. Henley Publishing Co.
2 West 45th St., New York City.

mam

I I ■ ««.■

THE HEY/ YORK

PUBLIC LIBRARY

ASTOR, LENOX
TILDEN FOUNDATIONS

• lA-LouHT Plant
' 2 -fiM€iagt erBody

- 3-Raddtr

- ^•Cltvator

PLATE I.— Part Sectloiul View of TTpical Airplane, Showing Inportanl Parts,

A COMPLETE, PRACTICAL TREATISE OUTLINING CLEARLY
THE ELEMENTS OF AERONAUTICAL ENGINEERING WITH
SPECLO. REFERENCE TO SIMPLIFIED EXPLANATIONS OF THE
THEORY OF FUGHT, AERODYNAMICS AND BASIC PRINCIPLES
UNDERLYING THE ACTION OF BALLOONS AND AIRPLANES
OF ALL TYPES. A NON -TECHNICAL MANUAL FOR ALL

STUDENTS OF AIRCRAFT.

THIS BOOK INCLUDES INSTRUCTIONS FOR LININQj UP AND

INSPECTING TYPICAL AIRPLANES BEFORE FUGBtT AND ALSO

GIVES EASILY UNDERSTOOD RULES FOR FLYING

BY,

Captain VICTOR W.SAGt, Sig. R. C, A. S.

MEMBER SOCIETY OF AUTOMOTIVE ENGINEERS; LATE CHIEF
ENGINEER OFFICER, SIGNAL CORPS AVIATION SCHOOL,
HAZELHURST FIELD, MINEOLA, L. I.

^OlVTAINS VALUABLE INSTRUCTIONS FOR ALL AVIATION STUDENTS. AIRPLANE

MECHANICIANS. SQUADRON ENGINEERING OFFICERS AND EVERYONE

INTERESTED IN CONSTRUCTION AND UP-KEEP OF AIRPLANES

^ SIMPLIFIED TEXT SUITABLE FOR SCHOOL OR HOME STUDY

NEW YORK
THE NORMAN W. HENLEY PUBLISHING COMPANY

2 WEST 45th STREET . , c

1918 ■■ " ' :• ' " ■ »

THE NEW YOP,?:

PUBLIC nBRARvl

839063

ASTOi^, LKKOX AND
TU-»JBM rOUHDATION-

The Norman W. Henley Publishing Co.

PRINTED IN U. S. A.

« "

• #

COMPOSITION, ELECTROTYPING AND PRESSWORK
** * B^lTHtf PUBLISHERS PRINTING CO., NEW YORK

• • •
• • •

• • •

PREFACE

•

As a result of considerable experience obtained last year in
instructing prospective aviators and mechanics, and in response
to an insistent demand, the writer prepared a treatise on air-
plane power-plants called "Aviation Engines," which has met
with a very gratifying reception and which is used by many
aviation schools as a text on this subject. Instructors who are
using the engine book successfully and niunerous students
who have derived some benefit from its contents have asked
for an exposition of the airplane in whict its operation and re-
pair principles would be written in the same simple non-tech-
nical manner as the treatise referring to power-plants.

To meet this demand, the present treatise has been prepared
and instructors, both civilian and army officers, who have read
the manuscript have pronounced the book as one well suited
for instruction work. It is not intended to be an engineering
treatise, nor is it intended to consider technical points that
can interest only the designer. At the same time, it is neces-
sary to consider some of the basic principles of auplane ffight
and aerofoil design m simple language so the student may
obtain a complete grasp of the subject. For those seeking
technicstl knowledge, numerous excellent reference works are
available. Very simple books for boys are also on the market,
so neither of these extremes has been considered in preparing
this text, because any need of the above can be met with
existing standard works.

The notes on inspection and lining up of airplanes have
been purposely made brief and apply to ahplanes m general,
a^ JnZ the specific type illustrated. TWs also appUes to
the mstructions, or rather observations, on flying which have
been suggested by a pilot of considerable experience. Every
eflfort has been made to explain all technical points and numer-
ous diagrams have been prepared to ampUfy the text. It is

vi ' The A. B. C. of Aviation

believed that this treatise, owing to its having been prepared
with a full realization of the average student's needs, should
be well adapted for instruction work on general principles of
mechanical flight and their practical appUcation in both
Ughter-than-air craft and airplanes. The book is as well
adapted to home study work as it is for classroom instructions.

The Author.

October, 1918.

ACKNOWLEDGMENT

The author desires to acknowledge the valuable assistance
given by 1st Lieut. Chas. A. Muller, Sig. R. C, A. S., who
was associated with him in mstructing flying cadets at the
Signal Corps Aviation School, Hazelhurst Field, Mineola,
L. I., in Aeronautical Science, and who furnished many ideas
for making this treatise one well suited for instruction work.
The wide experience of Lieut. Muller, who was a pioneer air-
plane designer and constructor, was utiUzed to good advantage
m checking up the manuscript and drawings prior to pubUca-
tion. Assistance given by Mr. Max Goodnough, Aeronautical
Mechanical Engineer, S. S. L., and the Engineering Dept. of
the Ciuliiss Aeroplane and Motor Co. also proved of value
m compiUng the origmal instructions for students which form
the basis of this treatise.

The Author.

October, 1918

Vll

TABLE OF CONTENTS

CHAPTER I

AIRCRAFT TYPES

Force of Air in Motion — ^Ascensional Power of Warm Air — Lifting Power
of Hydrogen-Gas — ^Tjrpes of Dirigibles — ^Why the Airplane is Best —
Attraction of Gravity — Elementary Airplane Principles — ^Kite Sup-
ported by Air in Motion — Air Resistance — ^Table 1: Resistance of
Aerofoil Sections — ^Table 2: Wind Pressure at Various Velocities —
How Airplanes Differ 13-27

CHAPTER II

LIGHTER-THAN-AIR CRAFT

Spherical Balloon Parts — Hydrogen Gas for Military Balloons — Control of
Free Balloons — Free or Captive Spherical Balloons of Little Value in
Mihtary Work — Kite Balloons Best for Observation Work — ^Dirigible
Balloon Types: The Zeppelin — Dirigible Balloon Types: The
Blimp 28-38

CHAPTER III

EARLY AIRPLANES AND GENERAL DESIGN CONSIDERATIONS

Henson Airplane — Philips Multiplane — Maxim's Flying Machine — Ader's
and Other Machines — First Flights of Wright Brothers — Lack of Speed
a Drawback — Plane Forms — Bird and Plane Form Compared — ^Air-
plane Moves in Three Planes — Table 3 — Birdflight Difficult to Imitate
— Comparing Airplane and Bird Flight — Plane Balancing Principles —
Airplane Control Methods — ^Use of Vertical Rudder 39-53

CHAPTER IV

DESIGN AND CONSTRUCTION OF AEROFOILS

How Planp Performance May be Gauged — Meaning of Lift and Drift — Lift-
Drift Value for Rectangular Plane — Meaning of Center of Pressure —
Properties of Cambered Aerofoils — Leading Edge Should be Curved
Down — Best Design of Cambered Aerofoil — Table 4 — ^Table 5 — Effect of
Wing Loading on Camber — Effect of Varying Lower Camber — Pressure
Distribution on Aerofoils — Position of Maximiun Efficiency — Position
of Center of Pressure — What is Meant by Critical Angle or Burble
Point— Greatest Lift Produced by Upper Surface— Table 6 . . . 54^-75

X Table of Contents

CHAPTER V

ARRANGEMENT, CONSTRUCTION, AI^) BRACING OP AIRPLANE WINGi

Monoplane or 'Biplane— Effect of Gap — Table 7 — ^Effect '•of Stagger — Plane
Forms — Securing Uniform Pressure Distribution — ^Airplane Wing Con-
struction — ^Wing Ck)vering Fabric — ^Why "Dope" is Used for Wings —
How Fabric is Fastened — ^Airplane Wing Bracing — Loads on Airplane
Wing Wires — ^Airplane Wing Form — Planes with Longitudinal Dihedral
— Influence of Lateral Dihedral — ^Airplane Wing Bracing — Side Bracing
of Airplane Wings — ^Airplane Bracing Wires — ^Typical Wire Bracing
Arrangements 76-lOJ

CHAPTER VI

AIRPLANE FUSELAGE CONSTRUCTION

Early Wright Starting System — Design of Fuselage Framework — ^Airplane
Design Considerations — ^Reduction of Parasitic Resistance — ^Airplane
Fuselage Forms — Complete Enclosure Important — How Coincidence
of Centers is Obtained — ^Landing Gear Forms — Wheel Tread Depends
on Spread — ^Woods for Airplane Parts — Metals Used in Airplanes —
Table 8— Table 9— Table 10 109-135

CHAPTER VII

AIRPLANE POWER-PLANTS

Aerial Motors Must be Light — ^Factor Influencing Power Needed — Airplane
Engine Forms — ^Airplane Engine Installation — Standard S. A. E.
Engine Bed Dimensions — InstaUing Rotary and Radial Cylinder
En^nes — Characteristics of Typical American Pre-War Aviation
Engines 136-151

CHAPTER VIII

AIRPLANE PROPELLER CONSTRUCTION AND ACTION

When Screw Works in Air — Mathematical Consideration of Propeller Pitch —
Propeller Definitions — Propeller Manufacturing Practice — Theories of
Screw Propeller Action — How Propellers are Balanced — The Disc
Theory— The Blade Theory 152-17(

CHAPTER IX

AIRPLANE EQUILIBRIUM AND CONTROL PRINCIPLES

Factors Regulating Equilibrium and Stability — Why Small Control Sur-
faces are so Effective — Control Methods of Early Airplanes — Standard
Control Systems of To-day — The Function of Balanced Control —
Why the Airplane is Banked in Turning — Instruments for Navigating
Airplanes — Suggestions for the Student in Flying — Run Motor Slowly
to Warm It — How to Take Off — How to Attain Altitude and Handle
Machine — ^Precautions When Landing — Danger in Stalling — Control in
MakingTums — Flying Learned Only by Practice — Important Hints . ITl-lOi

Table of Contents xi

CHAPTER X

UNCRATING, SETTING UP, AND ALIGNING AIRPLANE

To Unpack Cnrtiss Biplane — ^How Parts are Packed — ^Examination of
Parts before Assembly — ^Assembling Landing Gear to Fuselage — ^Panel
Assembly — Main Panels Joined to Fuselage — ^Adjustment for Dihedral —
Methods of Checking Dihedral — Checking Stagger — ^Wash-in • and
Wash-out — Tail Assembly — Landing Gear — ^Horizontal StabiUzer —
. Vertical StabiUzer — ^Elevators — Rudder — ^Aileron Adjustment — ^Rudder
Control Adjustment — Elevator Control Adjustment — General —
Checking Alignment of Wings and Fuselage — String and Straight
Edge Method of Lining a Fuselage — ^Typical Airplanes in Practical
Use 19&-231

CHAPTER XI

INSPECTING AIRPLANE BEFORE FLIGHT

Lispection of Propeller— Power Plant — Gasoline and Oil System — Cooling
System Parts — ^Landing Gear — Fuselage Nose — ^Wing Fittings —
Brace Wires-rStruts — ^Ailerons — Rudder — Stabilizers — Control Wires
—Fuselage Interior—Tail Skid 232-244

CHAPTER XII

STANDARD AIRPLANE NOMENCLATURE

Definitions of All Terms Used in Connection with Aviation Approved
by National Advisory Conmiittee for Aeronautics .... 245-257

THE A. B. C. OF AVIATION

CHAPTER I

AIRCRAFT TYPES

Force of Air in Motion — Ascensional Power of Warm Air — Lifting Power of
Hydrogen Gas — ^Types of Dirigibles — ^Why the Airplane is Best — ^Attraction
of Gravity — ^Elementary Airplane Principles — ^Kite Supported by Air in
Motion — ^Air Resistance — Table i, Resistance of Aerofoil Sections — ^Table 2,
Wind Pressure at Various Velocities — ^How Airplanes Differ.

The navigation of the air, which has been the dream of
mankind for ages, has only been reaUzed in recent years.
Practical aircraft have been built in definite forms that can
easily be classified, and also in several experimental types that
are little known and which have been discarded in favor of the
types known to be practical. The air is a gas that surrounds
the earth and which is said to extend above the earth's surface
for about 40 miles, though the density becomes less and the
air becomes rarer as the distance above the earth's surface
increases. Above a certain height, about four or five miles
from sea level, it is very difficult for human beings to breathe
because of the rarity of the air. We are so used to moving
about in the ak that many consider it an almost intangible
substance and do not reafize that 16 cubic feet of air will weigh
about a pound and that it exerts a pressure of about 15 pounds
per square inch surface on everything. We are so constituted
that this load is not appreciable to us any more than the force
of gravity. *

Force of Air in Motion. — Air in motion may exert con-
siderable force. A gentle breeze creates very slight pressure,
but a cyclone or hurricane, which means air travelling at a
rate of from 75 to 100 miles per hour, can do considerable
damage. Much destruction is caused by tornadoes due to
the great pressure of air travelling at a high speed, and which
has sufl^cient velocity to uproot large trees and tear buildings

The A. B. C. of Amotion

apart. Winds are caused by the conflict between rising air
currents due to the lesser weight of heated air which rises from
the earth's surface and the down currents of cold and therefore
heavier air which rushes down to take its place. The physical
contour of the earth and variations of temperature as well as
seasons of the year all have their influence on air movements
termed winds.

ASCENSIONAL POWER OF WARM AIH

The ascensional power of warm air was well known to the
ancients, and the first craft to navigate, or rather be supported

Fig. I. Non-ri^ Tj^pe Dirigible Balloon.

by the air, were very lai^ globular or pear-shaped bags of
paper or parchment filled with hot air and smoke from a fir^
burning beneath the opening in the bottom of the bag. A-
cork or piece of wood floats on water because it is lighter thar>
the supporting medium, a stone sinks because it is heavier
than water. A bag filled with hot air, smoke and gases,
resulting from combustion, is fighter than the surrounding cold
air it displaces and wiU rise because it is of lesser weight thaa
the supporting medium. The first airships were of the lighter
than air type and are called balloons. This type is made in.
two forms, aerostats or spherical balloons free to rise in the air
and blown hither and yon at will of the elements, and dirigible
balloons, which are driven by power and which may be steered

Types of Dirigibles 15

yy special directional membera or rudders. The free balloon
s of little value except for exhibition purposes. The kite
3alloon, however, which is held captive is a splendid type for
military observation purposes.

Lifting Power of Hydrogen Gas. — Practical balloons are
tnade up of various textile fabrics, such as silk or linen, which
are very closely woven and which are impregnated with rubber
compound to lessen the porosity in order that they may retain
gas. This cloth is cut into strips of the proper size and shape
which are sewed together to form the envelope or gas bag.
The seams are covered with strips of rubberized tap^ to insure
a gas-retaining joint. The bag is filled with hydrogen gas, the

Rg. 3. Side View of Tn>lcal B

I, Showing Important Parts.

lightest known element. One cubic foot of this gas is capable
ot lifting one ounce weight, therefore a bag with a capacity of
32,000 cubic feet would be able to lift one ton or 2,000 pounds,
^ weight including the gas, bag and basket and objects
raised from the ground. The kite balloons are shaped like a
% Bausage instead of a pear or globe and are allowed to rise to
tlie desired height by unwinding a cable from a power-driven
wincL

TYPES OF DIRIGIBLES

Dii^bles are made in two types, called non-rigid and
^d. The former class includes approximately cigar-shaped
Wis carrying a basket or body member suspended from the

]# The A. B. C. cf Ariation

bog hf A series of sliiig!, these bans attached either to a
Detling or to special fabric anchmage [Heces ^ewed to the bag.
The bag hr.4ds its sh^ie because it is distended by the intema]
gas preaenre. The ri^d type, of which the wdl-^nown ZeppeUn
airship ie an example, has a metallic fiameirork that divides the
main gas container into sections, the only function of the gas
hai^ bong to hold the gas. The framework shapes the bag
and permits of easy attachment of the "gondolas" or cars
carrying the power plants close to the body of the ship. These
types win be considtTed more in detail in proper sequence.

Heavier-than-air machines may be divided into three
types: airplaues, behcopters and oimthopto^ The first

f^mrtrPtaa*. Jfadf

Tractor Screw' '^f^l^-WWee/

Fig. 3. Tractor B^Une in FUglit. ' .

named is made in three different patterns designated by the
number of supportii^ surfaces or wii^ it has. A monoplane
has one wing; a biplane, two; and a triplane, three. The heli-
copter is a machine that depends on lifting screws for snstenta^
tion and propellers for securing movement in a horizontal plane.
The omithopter is a type devised to imitate bird flight and
sustentation is supposed to be derived by the flappii^ of wings.
Neither of the two latter forms is practical or seems to have
any future.>^he airplane in its simplest or monoplane form
comtists of a body to carry the pilot, power plant and controlling ■
members, supported by wings, one at each side of the body.
The engine turns an aerial propeller which pulls the machine
through the air because the air pressure imder the wing and

Why the Airplane Is Best 17

the suction effect on top of the wing exerts a lift greater than
the weight of the machine if it is drawn through the air with
suflBcient speed^ The airplane in its various forms will also be
discussed in succeeding installments. The airplane is the most
practical type of machine to navigate the air and thousands
are in daily use. Its principle of operation is easily under-
stood. /If wind moving at high velocity exerts pressure,
drawing an object through the air at high speed will produce
pressure against it. If this is a plane section, such as a kite, it
will rise because of the wind beneath it. Airplane wings may
be compared to a kite, the propeller thrust or tractor screw
pull can be likened to the tension of the kite string when one
runs along the ground to raise the kite.T

WHY THE AIRPLANE IS BEST

One can hardly conceive of a man even of enormous wealth,
who would maintain an ocean liner for personal gratification
or as a means of obtaining pleasure. It is evident that amuse-
ment and recreation could be secured at much less expense by
the use of smaller and no less practical craft. This is really
the condition that obtains in the field of aeronautics, and before
the problem of aerial navigation can be said to have been solved
it will be necessary to produce practical creations which will
be light, speedy and mechanically reliable. One must look
to the heavier-than-air class to find flying machines which give
promise of becoming sufficiently practical so as to be within
the reach of the average prospective user. The principles
imderlying the construction of lighter-than-air craft are such
that extremely large sized balloons must be built, because the
small lifting power obtained by the use of the Hghter gases
than air is wholly disproportionate to the large dimensions of
the gas container.

The most practical flying machine, the airplane, depends
upon the correct application of aerodynamical principles.
Yet, while flying machines in a large sense may be said to
include all devices that have contributed to assist man to fly,
besides the use of the gas bag, the only form that has at-
tained success is the airplane. This machine is capable of

18 The A. B. C. of Aviation

movement in any direction, as in a vertical or horizontal plane
or any angular component of the two, by the aid of simply con-
trolled members which are easily installed on the machine itself
and actuated by the pilot. There are three classes of flying
machines. Those that seek to sustain themselves as birds do,
by flapping wings, are known as ornithopters. Other types have
been built in which a lifting actionals secured by aerial screws,
but none of these have been devised that have produced results
sufficiently great to warrant further development of this type.
The third class includes the airplane and is the most practical.
There are two retarding forces to be overcome in securing suc-
cessful mechanical ffight, those having to do with gravity and
others that are due to wind or air resistance.

ATTRACTION OF GRAVITY

We will first concern ourselves with the attraction of
gravity. Every mass of matter that is near the earth, if free
to move, pursues a straight Une toward the center of the earth,
and the force by which this motion is produced is called
gravity. At the same distance from the center of the earth
the gravity of different objects varies as the mass. If a bo(]^
is not free to move, its tendency to go toward the earth's center
causes pressure, and the measurement of this pressure is called
the weight of the body. Weight is usually employed as a
measure of mass. The more the pressure of a body is towards
the earth's center, the greater its weight. The body that is said
to be the Ughtest is one that has the least gravity attraction.
The attraction of gravity varies directly as the mass, the greater
the mass the greater the force acting to bring it towards the
earth's center; the nearer the earth's center the less the at-
traction. A body 2,000 miles imder the earth's surfac^ would
be attracted with only half the force that would obtain were
it at the surface. It is at the surface of the earth that this
force is greatest and at great heights it is less. For example,
4,000 miles above the earth's surface gravity is four times less
than it is at the earth's surface. At heights at which it is
possible to carry on experiments the variation is very slight
and may be regarded as negUgible. 1 It will be evident that one

Elementary Airplane Principles 19

of the most important forces to be overcome in flying machines
is the attraction of gravity, and considerable power will have
to be utilized for this purpose alone. ^

ELEMENTARY AIRPLANE PRINCIPLES

In order to secure a good understanding of airplane operat-
ing principles it may be well to mention that airplanes of the
present day are really developments of the box kite, and that
comparisons can be made with well-known apphances such as
the sails of boats, to make clear some of the principles upon
which airplane flight is based. For simpUcity of presentation
we can consider the boat sail as an example to show the pro-
pelling force of the atmosphere in motion which, as outUned in
the first installment, is termed wind. Any object which can
be tensed or tightly drawn so that the wind will exert pressure
upon its broadest area will create power in proportion to the
velocity of the wind and the area Exposed to the air pressure.
This, of course, means that the object or plane must be at
approximately right angles to the relative wind, which is not
true of the Ufting surface of an airplane, which is incUned at
angles ranging from 2 to 14 or 15 degrees as a maximum with
the relative wind. Perhaps the most famiUar illustration of
wind power is the wind-mill, and the toy pinwheel is a device
by which any child is capable of unconsciously observing that
air in motion will create power or do work.

KITE SUPPORTED BY AIR IN MOTION

With the kite attached to the ground by a string and
depending upon the velocity of the wind under its surface to
elevate it, and a balancing device in the form of a tail to main-
tain steadiness, as shown at Fig. 4 A, we have one example of
the use of air pressure to sustain weight. In the boat sail,
which is capable of overcoming the resistance of the water on
the hull by using the wind as a propulsive force, we have
another example of how the wind may be made to do work,
while in the airplane we have to a certain extent the principle
of a box kite as far as its capacity for sustaining weight is

20' The A. B. C. of Aviation

concerned by air pressure. Instead of being dependent
the velocity of the wind as a kite is, an airplane is t
against the air by means of one or more aerial screws '
are revolved by suitable prime movers, usually an in*
combustion engine as shown in Fig. 4 B. This prop
force is utilized for a twofold purpose. In the first pla
permit the direction of motion of the airplane to be
pendent of the wind direction and also to retain a susti

DifcHonofKlfaPull

Ralahve Wind

I^. 4. Ditgnms Comparing Actioii of Wind mi Kite and Ait Pressnn
Ain^uie V%i£s.

force under the planes r^ardless Of the direction of a
pheric flow.

It will be apparent upon reflection that if the kite i
Godered a reversed boat sail and then when again revers
instance or illustration of the airplane supporting surfi
will be e\ident that in the three there is but one prii
though it is differently applied. In the same manner in
varjiog power may be secured by altering the preesi
the atmosphere on the sail of the vessel by changing its
tion, it will be seen that varying the angle of the plane !
air that it is possible to vary the degree of sustaining •
It is apparent that airplanes must be proportioned with i
oi ha^nng mi nimu m resistance to the wind, and it must

Air Resistance

jsult without sacrifice of lifting effect or sustaining

AIR RESISTANCE

3 factor of air resistance is a very important one which
)e given careful consideration by the designer of aerial

W/nof D/recf/on

Fhiv around Body with poor
^am Line Form. Note formafion
'Jddies and large area of
Negative Pressure

'.111} i

of/bsrffve
yre least
Tail

Air Flow around Body with gooa
Stream Line Form. Note absence
of Eddies and very small area
of Negative Pressure

How Positive ^

U' and Negative \'

T pressures are

Distributed

around $ody of

good Stream Line

Negative
Pressure

V of Afrstream around
of oil Section which may
zonsidered an Element
^ody of Good
iam Line Form

ction of

til Movement

• Value of Positive
Pressure greatest,
at Nose

Air Stream deflected by
curved Aerofoil entering
Edge

'Area of Low :•':::[

Pressure results in ■

Suction Lift:':-:'.

Line of Flow of Relative Wind •

,•' Angle of
^Incidence of
Aerofoil

Diagrams Showing Air Flow Around Various Bodies and Positive and
Negative Pressures Produced by Air Currents.

It is of considerably greater moment than one would
\ on first thought. The shape of the object being forced
h the air (or, in fact, any other gas or fluid) will have

The A. B. C. of Aviation

material bearing upon the resistance offered to its passage.
A '^ streamline'' body has the least resistance. Air resistance
has been estimated to increase as the square of the velocity, so
it will be seen that at ten miles per hour atmospheric resistance
is four times what it was at five miles per hour; at 50 miles per
hour, which is ten times the speed of five miles, the air resistance
will be a hundred times as great. It has been found that air
currents moving at the rate of 60 miles per hour have a pressure
of approximately 17.7 pounds to the square foot, and from this
basis the indication of almost any speed may be determined
with reasonable accuracy. As an example of the ratio of in-
crease of resistance with augmenting velocity, the following
table, which gives the effort required in the horse-power to
move a body through the air for each square foot of surface
exposed at right angles to the relative wind, will prove of
interest. In this case it is well to know that the horse-power
required increases as the cube of the velocity, whereas air
resistance augments as the square of the velocity.

TABLE I

Miles per Hour

Feet per Second

H.P. per Sq. Ft.

10 ■

14.7

0.013

0.044

24.6

0.105

36.7

0.205

0.354

58.7

0.84

73.3

1.64

87.9

2.83

117.3

6.72

100

146.6

13.12

RESISTANCE OF AEROFOIL SECTIONS

The resistance of plane or aerofoil sections is not nearly as
great as that of spherical, cylindrical or rectangular bodies.
To begin with, the planes are usually inclined at small angles
to the relative wind, and never at an angle of more than 16
degrees, because in the ordinary aerofoil when this point is
reached the lift becomes greatly reduced. \ As the plane

Resistance of Aerofoil Sections

progresses through space with suflScient velocity to obtain a
sustaining influence due to the air beneath it, it is thus able to
overcome the attraction of gravity /^I^ this connection it is
weU to state that the lift on the or^ary auplane wing section
is not due solely to air pressure on the lower surface of the
aerofoil, but, on the other hand, a study of the diagram at
Fig. 5 will indicate that there is a pronounced suction effect
acting at the top, because there is an area of reduced or nega-
tive air pressure which, of coiu^e, contributes materially to the
total lifting effect. It is stated that this area and the attending
lifting influence will vary with the shape of the aerofoil, and
that this will also depend upon the aspect ratio of the plane,
the angle of incidence and the velocity with which it is passing
through the air. /^^io Uft the plane, therefore, we must have
both compression imder the bottom surface and partial vacuum
at a portion of the top surface, the direct pressure produced
by the former and the increase of Uft produced by the yielding
of the other raise in ratio with velocity of the air. It is ap-
parent that the movement of the air or velocity of the wind
must be sufficient to cause a partial vacuuniabove and com-
pression below to secure mechanical flight J The following
tabulation will give the wind pressure per square foot at the
different velocities: •

TABLE II

Wind Pressure at Various Velocities

Feet
perSeoond

Velocity
Feet per Min.

Miles
per Hour

Pressure
per Sq. Foot

1.47

.005

7.33

440

.123

14.67

880

.492

36.6

2200

3.075

73.3

4400

12.3

102.7

6160

24.103

146.6

8800

100

49.2

The figures given above have been determined by con-
sidering the pressure of the wind upon a fixed object, but there
b probability that there would be some departure from these

24 The A. B. C. of Aviation

values in the event of an object being driven at the speeds
indicated against the atmosphere. The table is, therefore, of
value only inasmuch as it shows that with the increase in
velocity there is a great increase in pressiu-e, which obviously
can be taken to mean that there would be a greater sustaining
force when the plane is placed at its most advantageous angle
of inclination with the relative wind, because it is at this point
that the greatest lifting effort will be seciu^ed with a miniTnnm
of resistance.

The effect of the strength of wind at higher velocities is
well known and can be easily imderstood by any one who has
flown a kite. On a windy day there was a much greater pull
upon the string than when the movement of the air was less
and, unless a favoring air current was found, it was almost
impossible to keep the kite in the air imless one exerted a
pronounced pressure imder the kite by running along the
ground in order to draw it through the air by means of the
restraining cord. In still ah- the kite will not raise itself from
the ground, and it will fall as soon as the wind produced by
drawing it through the air stops. It will be evident therefore,
that if one or more surfaces of the usual aerofoil section are
attached to a frame that is capable of sustaining a motor for the
purpose of drivin^the apparatus forward by means of fan
wheels or aerial screws, and if the surface curvature and area
are sufficient to displace the air to an extent capable of exerting
a vertical component reaction called Uft, which must be
greater than the entire weight of the apparatus, we have
contrived an airplane which will be capable of flight. The
amount of power required depends upon many factors, and as a
general rule the greater the surface of the airplane the less the
speed that is necessary to drive it through the air to secure
, sustentation and the less the amount of power required to lift
it from the ground.

HOW AIRPLANES DIFFER

For this reason airplanes designed to carry loads usually
have a large surface, moderate power and relatively slow
speed. High-speed airplanes have small surface and high-

How Airplaties Differ

f?o fa ry Cylinder

Sngi'ne ^\ Balancing -Upper PMne

Toil Plane '•, ''''^P.

Kg. 6. Three Main Types of

Airplanes. A. Monoplane. B. Biplane C
Triplane.

The A. B. C. of Amotion

^ \

IS.

llll ?

t-f

1^5'^//

' \f

»^

i -S" g idt\

-C

i 'o '^[/L

■ V

llj

r^J

iF^OS

><-.^

•5

^ ^

)

1 ^

|Fi '

z&'l

■ft

1W ''

;

ti.

1 ^

How Airplanes Differ 27

capacity power plants. Airplanes are made in three main
types — the monoplane as shown at Fig. 6 A, the biplane out-
lined at B, and the triplane as depicted at C. If the machine
has the air screw moimted in front, it is called a tractor; if the
power plant and screw are mounted in the rear of the pilot as
at B, it is called a pusher. Machines intended to rise from
and land on water are called '^ seaplanes" or hydroaeroplanes
and are provided with floats instead of wheels. The pusher
biplane shown at Fig. 6 5 is provided with floats instead of
wheels. The appearance of a fast one-place scouting or
fighting plane is shown at A, Fig. 7. The conventional two-
seater used in this country for training purposes is shown at B.
The former is capable of a speed of 120 miles per hoiu-, the
latter will not fly faster than 80 miles per hour.

CHAPTER II

LIGHTER-THAN-AIR CRAFT

Spherical Balloon Parts — ^Hydrogen Gas for Military Balloons — Control of Free
Balloons — ^Free or Captive Spherical Balloons of Little Value in Military
I Work — Kite Balloons Best for Observation Work — ^Dirigible Balloon Types

' —The Zeppelin— Dirigible Balloon Types— The Blimp.

The reason why aircraft of the lighter-than-air type leave
the ground is a simple one. It is known that there are a
niunber of gases which are lighter than air, e.g.j coal gas and
hydrogen. The amount of lift possible depends upon the
^ "buoyancy" of the gas, which is the difference between its
weight and the weight of an equal voliune of air. If one has
an imderstanding of the approximate buoyancy of the gas used
as a lifting mediiun, it is very easy to compute the lifting power
of a given quantity of this gas. A balloon with a capacity of
16,000 cu. ft. of hydrogen, if it is filled at the sea level and at a
temperature of 60 degrees Fahrenheit, will lift about 1,000
pounds. This, of course, including the weight of the gas and the
container; and a balloon capable of lifting 1,000 pounds would of
itself weigh about 550 poimds ; this means that the envelope or
container, the net-work, the observation car and the equipment
it carries, as well as the weight of the gas, are all considered.
The lifting power of a balloon of the same size filled with coal
gas would be no more than 600 pounds. It will be evident that
to hf t a given weight with coal gas that it will be necessary to
use a container holding nearly twice the quantity that is
needed to handle the same load with hydrogen gas.

SPHERICAL BALLOON PARTS

The parts of a spherical balloon are clearly shown at Fig. 8,
and may be readily understood. At the top of the main con-
tainer, which is made of some fabric chemically treated to
prevent leakage of gas, is placed an escape valve which is kept

Spherical Balloon Parts 29

seated by pressure of the gas from the inside, and which can
be opened only by pulling a cord convenient to the aeronaut
who is in the basket. The function of this valve is to permit
of a certain degree of gas escapement, which can be controlled
by the operator when it is desired to descend. As soon as the
operator ceases to exert pressure on the valve cord, the valve

. .-- Gas Escape Pblve
- Valsfe Rope

Fig. 8. Simple Free Balloon of the Spherical Tj^ with Parts Designated.

closes and prevents further escape of gas. It will be evident
that when it is desired to descend from any altitude, that a
decrease in the hfting power of the gas bag would permit it to
settle to the ground. There is an open neck at the bottom of
tlie gas bag to permit the gas to escape when it expands, as it
would do when coming into warm sunshine. The heat pro-
duces an expansion and increases the volume of the gas. It
will be apparent that unless some means were taken for relieving

30 The A. B. C. of Amotion

this excessive pressure, that it might disrupt the gas bag; there-
fore, as the gas expands it rushes out of the gas bag through
the open neck at the bottom. If for any reason the sun
should be obsciu-ed by clouds or there should be "considerable
moisture in the air, the cooling of the gas will result in its
contraction, and there should be a corresponding reduction in
volimie; the lifting power of the balloon is therefore impaired,
inasmuch as the lifting abiUty is the ratio between the weight
of the gas carried and the amount of air that it displaces. In
order to keep the balloon from falling too rapidly, and to offset
this condensation of the supporting gas, it is necessary for the
aeronaut to throw off ballast usually carried in the form of
sand, imtil a state of equihbrimri is reached and tmder which
conditions the balloon will stay up as the decreased weight
carried is proportionate to the lifting power.

When it is desired to make a rapid descent in order to
avoid an approaching storm, or for any other reason, the
escape valve is kept open until the balloon begins to settle,
and when it has reached a point near the ground the operator
will pull the ripping cord and tear away the ripping panel,
which is normally sewed to the bag, in order to provide a large
outlet for the sudden escape of gas. A grappling hook is car-
ried to permit of securing an anchorage to any convenient
tree or fence, and in addition a drag rope, which may be
dropped for 100 feet or so below the car, is provided so that it
may be grasped by people on the ground who would assist
in bringing the balloon to a stop.

HYDROGEN GAS FOR MILITARY BALLOONS

Owing to the high cost of hydrogen gas, balloons that have
been used for ordinary observation purposes are' filled with
coal gas, but in all military ballooning the gas bags are filled
from compressed hydrogen tubes. It will take about 5 hours
to fill a large balloon with coal gas, whereas when the hydrogen
is carried in tubes in which it is held under high pressure, less
than one hour suffices to fill the bag. Owing to the ease with
which hydrogen may be carried when it is contained in tubes
under pressure, it is always considered best for miUtary pur-

Control of Free Balloons 31

I)oses. Relatively simple hydrogen making plants have been
devised which may be carried in the field in the event of the
supply of compressed hydrogen tubes giving out.

CONTROL OF FREE BALLOONS

It will be noted with a free balloon that there is no move-
ment of the balloon relative to the air, as is true of an airplane
or dirigible airship. A balloon must move with the air cur-
rents in which it is supported. The only control the aeronaut
has over the movements of the balloon is to vary its altitude
and attempt to seek air currents or winds flowing in the direc-
tion in which he wishes to go. The material ordinarily used
for making gas bags is silk, though cotton has been employed.
The balloon is surroimded by a netting of cord from which
cords used to suspend the basket radiate down to a hoop or
spacing member of steel, which keeps them separated by the
proper distance and prevents them from getting tangled. The
baskets are usually of wicker work. Another use for the drag
or controlling rope besides that of providing a convenient
means of having people on the ground assist in bringing the
balloon to a stop is to preserve equilibriiun at low altitudes;
when the rope is trailing, a certain portion of its weight is
supported by the ground, but as the balloon tends to settle
more of the rope will be supported by the ground, in which case
we have exactly the same effect as though an amount of ballast
equal to the weight of rope dragging on the ground had been
thrown out of the basket. This reUeves the balloon from some
of its burden. Then agam, if the baUoon should tend to rise,
some of the rope will be lifted from the ground and the extra
weight will tend to check the ascent of the gas bag.

FREE OR CAPTIVE SPHERICAL BALLOONS OF LITTLE VALUE IN

MILITARY WORK

Free balloons have no definite value for military purposes
because of the imcertainty attending their use; there is no
guarantee that a balloon of this nature would reach any desired
point when released, inasmuch as its voyage would depend

The A. B. C. of Aviation

entirely upon atmospheric conditions. A cold, wet day woul^
produce rapid condensation of the gas, shortening the diu-atioJ^^
of the flight, whereas the operation on a warm day would b^
much more satisfactory inasmuch as the time of flight, would
be greatly extended — then again imf avorable winds might blow
the balloon out of its course.

The ordinary form of spherical balloon is of little value as a
captive balloon for miUtary observation because of its action
when restrained from movement. Reference to the illustration
of Fig. 9 will demonstrate clearly why the spherical type is not

^^ Anchorage .

Fig. 9. Why Captive Spherical Balloons Are Not Suited for Observation Woik.

the type for military observation purposes under ordinary
conditions. If one refers to A in this illustration it will be
observed that in an ascending air current the balloon will ride
in a position that will readily permit of observations being
made; however, should the wind change, and instead of being
moderate in velocity assume any speed, it will tend to move
the balloon along with it, and the restraining rope, which is

Kite Balloons Best for Observation Work 33

anchored to the ground will, of course, keep the balloon from
moving. The result is that the balloon becomes inclined to a
degree that makes it v^ry dangerous for the observer, and as
it would be swaying violently it would not permit of any obser-
vations of value being taken. The condition under which the
balloon would work in a wind is shown at B.

KITE BALLOONS BEST FOR OBSERVATION WORK

The kite balloon, such as shown at Fig. 10, is the type that
is best adapted for captive balloon work. In this balloon, by
changing the shape of the gas bag and by the addition of supple-

N^ Balloon Hndsio rise
\jnftiisdfrecfion

&as Coniaimr

Drflatmg Sleeve

«-e.«r***"'°°°"^^*''""

fail Parachutes

%^^^'*A,rlnletf

'Anklet 1 //
toA^dder//

*^DirecHon
■^ ofWir>d

S^-Anchorage Cable
\faConfrol

\^round

^^-Car

l^opes for hand ling
when near ground- "■

D!recHonof\\
Winch Pull ^

Parts of Typical Kite BaUoon.

mentary tail members, it is possible to have the balloon act just
as a kite does, and remain reasonably stable in winds of some
magnitude. The construction of a typical kite balloon used for
military observation purposes is shown at Fig. 10. This con-
sists of a main bag of gas-retaining material m which a smaller

34 The A. B. C. cf AriaHon

bag called a ^'balloonet" is placed. The function of the baL
loonet is to be filled with air which rushes into the opening ani
takes care of any expansion or contraction of the gas in tb
main bag. When the gas in the main bag expands under tb
influence of the sun's heat, the air in the balloonet can flow ou
through outlets, as indicated by the small arrows AA, tha
communicate from the interior of the balloonet to the suppl
mentary air bag or air rudder attached to the bottom of tb
main gas container. As the air rushes into the opening of t
air rudder and passes out of the way it will be apparent tha
as the velocity of the wind increases its speed through the air
rudder bag will increase, and that it will tend to keep the
assembly steady, as a tail assists in keeping a kite stable; by
the use of a tail cable carrying a nmnber of parachutes or in-
verted cones, which can fill with air, a further steadying
influence is obtained that will keep the balloon from swaying
unduly. The pull on the anchorage cable is such as always to
keep the balloon in a certain position relative to the air, and as
the shape of the container is that of a sausage the air actually
assists in keeping the balloon up. Many himdreds of these
observation balloons are in use on the battle fronts and form
an invaluable method of enabling military observers to gauge
the acciu^acy of fire of the batteries imder their control.

DIRIGIBLE BALLOON TYPES — THE ZEPPELIN

For offensive purposes the Zeppelin type of airship has
received considerable use by the Germans. The Zeppelin
airship depends upon numerous independent gas bags ranging
in number from 18 to 23, which are held in a lattice work of
aluminum metal, so as to form a cylinder with conical ends
having from 16 to 20 sides when viewed as a cross-section;
each of the gas bags has the usual form of deflating valve and
also is provided with an automatic safety valve to permit the
escape of gas from the bag if the pressure becomes too high.
The capacity of some of the latest Zeppelin types varies from
800,000 to 1,200,000 cu. ft., and the dimensions range from
450 to 550 ft. in length. The diameter varies from 40 to 50 ft.
A number of gondolas or cars are attached very close to the

Dirigibk Sallom Types— The Zeppelt

3C The A. B. C\ cf Ariaticm

{raaaewoA ^arryiiig the gas bags, and have douMe bottoms
saA arc prorrided with shock abeoibers so that the Zeppelin
HUT 4es0XDd oa both land and water. The rigid type of
erjAstriKtioD permits o€ mudi greater speed than can be
iKieiired with the "Blimp'' deagn* because their shape varies
to a degree as the pressure insde o€ the ba^ varies. The
ext^^mal frj^m «€ the Zeppelin, which is regulated by the in-
Ufnfw framework construction, does not aha* its shape.
Air>ther thing is that the Zeppdin does not only depend upon
the lift fA the gas it contains for ascent and descoit, but it is
prffvided with horizontal rudders or elevators which can be
tilted upwards to give a certain lift when the ship is proi)elled
in a forward direction.

The long imder-surf ace of the airship itsdf also acts as an
elevator as it is driven at high speed throu^ the air. Owing
to the small size individual gas bag3 the Zeppelin airship does
not need ^'balloonets/' as the gas expansion is tak^i care of
by the automatic valve. Between the gas chambers and the
framework is a space which is filled with non-combustible
gas in the war craft in order to serve as some protection from
fire. Another thing — ^this inert gas tends to shield the hydro-
gen gas to some extent from changes of temperature. These
airships are usually provided with water ballast and use several
high-powered engines for propulsion. Fom: propellers are
ixsed, these being attached to the framework of the airship and
driven from the engines carried in the cars by means of gearing.
The Zeppelin is capable of attaining speeds as high as 50 or 60
miles per hour against mild winds, and as it is provided with
Htabilizing planes and other surfaces that act as elevators to
taim or depress the airship, it can be readily controlled. The
K^ bags are in place inside of the framework; the entire frame
ttHH(;mbly is covered with a special fabric which is coated with
an aluminum powder compound to increase heat radiation and
to njduce the risk of fire. The Zeppelin balloon, however,
owing to its large size, is very vulnerable and is much easier to
hit with anti-aircraft guns than faster and smaller airplanes are.

Dirigible Balloon Types— The Blimp.— The ''Blimp" type
of balloon is a non-rigid form in which the shape of the gas bag

Dirigible Balloon Types — The Zeppelin

^ The A. B. C cf Anatian

ift msdMaaned by m»ms of an intmor baDoooet wMch may
he fined with sir &tber from the ^q> stream, of the pn^ieller or
hy meaim of a separate btow^- omfit driven by an auxiliary
pr/wi^ l>Iant of the gmaTl air-eooled engme form as used for
motorryele propulsion. The amount (rf air entering the bal-
loontf^ can be controlled by the operator and^ of course, depends
^mtirety upon the condensation or ^^nnstm of the gas used
inski(ie of the bag as a lifting medium.

A typical ''Blimp" is shown at Fig. 12. and this type of air-
craft 18 receiving considerable application fcHr patrolling pur-
pofteft. It h, capable of reasonable speed in the latest types,
vrhich are provided with engines of 100 cwr more horse-power,
and fa fjf especial value in hovering over the sea to locate the
prcfi^mce of .submarine boats. The usual construction is to use
a 7*pecial dgar-shaped bag. or one with a proper streamline
form a^i will provide for minimum air resistance and ordinary
airplane type fuselage, with places for two operators, suspended
from the bag by means of the usual suspension wires. These
are capable of speeds from 35 to 45 miles per hoiur and are
provided with lifting planes and rudders to faciUtate control.
Where the lifting planes are used it is not always necessary to
change the amount of gas in the container or to throw out
ballast to obtain diflferent altitudes. These change may be
rihtained by manipulation of the rudders, and as the gas is
retained for longer periods it is possible to make longer trips
without excessive wastage of gas.

CHAPTER III

EARLY AIRPLANES AND GENERAL DESIGN CONSIDERATIONS

Henson Airplane — ^Philips Multiplane — Maxim's Flying Machine — ^Ader's and
Other Machines — ^First Flights of Wright Brothers — ^Lack of Speed a Draw-
back — Plane Forms — ^Bird and Plane Form Compared — ^Airplane Moves in
Three Planes— Table 3— BirdfUght Difficult to Imitate — Comparing Air-
plane and Bird Flight — ^Plane Balancing Principles — ^Airplane Control
Methods — ^Use of Vertical Rudder.

Henson Airplane. — One of the first machines built to
operate on airplane principle was devised by an Englishman
named Henson, and was built in 1843. This consisted of a
light framework of wood, covered with silk, about 100 ft.
broad and 30 ft. long and was slightly bent upward at the front.
A rudder approximating the shape of the tail of a bird, which
was 50 ft. long, was used to steer it in a vertical direction.
The car was placed below the main plane and contained the
steam power-plant and also provided room for the passengers.
Propulsion was to be obtained by two propellers which were
placed on either side of the car, and it was proposed to regulate
the speed of these. By having the propellers moimted on a
imiversal driving joint it was proposed to assist in turning the
machine to the right or left by tiu*ning the propellers, so that the
thrust would be exerted on an angle instead of in a straight line,
as was required to seciu^e normal flight. Owing to very low
horse-power and great weight of the power-plant, the engine
developing but 20 H.P., the machine was not capable of leaving
the ground. Had the modern Ught-weight high-powered in-
ternal combustion engine been available, there is no doubt but
that this machine would have been able to leave the ground
imder its own power, though, of course, in the Ught of our
present knowledge its speed would have been low, its flying
action very poor, and it would not have been capable of
making any sustained flight.

40 The A. B. C. of Aviation

Philips Multiplane. — Horatio Philips, another Englishman,
built a very peculiar form of airplane flying machine in 1862.
This model had a supporting wing area composed of a very
large number of very narrow surfaces with a long advancing
edge, the pliu'aUty of planes being carried in a frame, so that
the entire contrivance resembled a huge Venetian blind. The
height of the frame was about 10 ft., the breadth was 21 ft.
The whole was mounted on a wheeled carriage shaped like a
boat which was about 25 ft. long. It was operated over a
circular board track and was anchored by a rope in the model
to the middle of the track. The weight was less than 300 poimds
and tests show that a dead weight of 72 poimds placed over the
front wheels could be lifted 30 ft. in the air when proper speed
had been attained. This proved that airplane surfaces were
capable of supporting weight by air reaction. Owing to trouble
with the power-pl^,nt very Uttle else was done.

Maxim's Flying Machine. — A well-known scientist, Sir
Hiram Maxim, carried out some very interesting experiments
in 1881 with a very large flying machine built on airplane
lines, which is said to have cost over $100,000. This consisted
of a large main supporting plane with a nmnber of smaller
aerofoils to the right and left of it, the whole having an
available supporting area of 3,875 sq. ft. The planes were
connected to a platform 40 ft. by 8 ft. by means of a frame-
work built of thin-walled steel tubes, this platform forming the
support for the boiler and engine. The diameter of the pro-
pellers was over 17 ft. The vertical movement of the machine
was controlled by two horizontal planes, one of these being
placed at the front of the machine, the other at the back.
Horizontal movements were to be controlled by two planes
inclined to one another at an angle of about 8 degrees and
arranged on either side, so as to be capable of being raised or
lowered. The result of this movement was to shift the center of
gravity and consequently alter the direction of motion. The
entire machine weighed 7,000 pounds, and in the experiments it
was mounted on four flanged car wheels and operated on a
railroad track. In order to control the upward motion of the
machine an overhead rail was placed over the top. With a

Early Airplanes and General Design Considerations 41

steam pressure of 300 pounds (this machine being driven by
steam, as it was the only power-plant then available) the
machine rose from the lower rails and came into contact with
the upper ones. During a test made some time later the upper
rail was broken as a result of the impact and the machine flew
across a field, and on landing was partially destroyed. This is
the first record of a successful flight by a heavier-than-air
machine in which the propulsive power was fiunished by a
power-plant forming a part of the machine structure. The
dynamometer test showed that a dead weight of 5,000 pounds
would have been Ufted, and as can readily be seen, had the
modem internal combustion engine been available, it is con-
ceivable that aerial flight might have been solved years earlier
than it was. It was about this time that Daimler was per-
fecting his first crude internal combustion motor, which at that
time was not built in multiple-cyUnder forms, but only in the
simple single-cylinder and two-cylinder V types. These ex-
periments would lead one to beUeve that it is possible to build
airplanes of considerably greater weight than any which have
been so successful in modern flying.

Ader's and Other Machines. — Among the later creations
which must be mentioned is the type shown at the Paris
Exposition in 1900, which was devised by a French engineer
and electrician named Ader. The planes were of a pecuUar
form and in the nature of wings which could be folded back.
Two propellers were employed, each with 4 blades, and despite
the -fact that compressed-air motors were utiUzed to drive the
propellers and that the machine weighed over 1,000 pounds, it
managed to make short flights and demonstrated that it was
capable of lifting its weight from the ground. An Austrian
by the name of Kress tried out a machine near Vienna in 1901
with results that gave considerable promise, and the experi-
ments made >l)y the late Professor Langley at Washington,
D. C, resulted in the first flight of over a mile by a heavier-
than-air craft. This was made by a model plane of his design
on December 12, 1896. The experiments of Prof. Lilienthal,
a German, who was studying the problem of soaring by means
of ghders and the experiments of the Wright Brothers, in this

42 The A. B. C. of Aviation

country, produced real results that were later turned into
account in building power propelled airplanes.

FIRST FLIGHTS OF WRIGHT BROTHERS

The flights made in 1903 by the Wright Brothers, who
built an airplane which was equipped with a motor of their
own construction, was really the first development of a type
that was at all similar to the machines used at the present time.
Even at the early stages of the development they were able to
make flights of over 1,000 ft., but owing to the secrecy with
which they worked and the isolated points at which their
experiments were carried out, but little was thought of their
accomplishments by the world at large. Later developments
have proved that even at that early date they were far ahead
of their contemporaries, because they were working on inde-
pendent lines and developing new features of construction
instead of trying to improve or re-adapt the principles that had
been discovered to apply to the very early types of unsuccessful
flying machines. It will be understood that in referring to
these as successful flights the description is but a relative one,
because at that early date any machine that would leave the
ground and fly for a few hundred feet at an elevation of 8 or
10 ft. was considered to be a practical flying machine.

LACK OF SPEED A DRAWBACK

It required long development and continuous experimenting
to develop the modem forms which are capable of making
sustained flights for hours at a time at extremely high speeds.
One of the difficulties met with in the early types of machines
was the provision of power-plants of inadequate capacity. A
theoretical consideration by the early engineers working on
mechanical flight outUned that flight would be possible with'
considerably less power than is now utiUzed, but the machines
of that period were very flimsily built and therefore very light
and did not fly at very high speeds, so that power-pleuits of
30 or 40 H.P. were sufficient to handle the requirements of
flying under favorable conditions. It was learned later that

Plane Forms 43

reserve p6wer was needed in order to seciu^e flights and to
overcome unfavorable atmospheric conditions. In order to
secure relative speed it is imperative that the speed of flight
be very much greater than any of the winds one would be apt
to meet with while flying. A table showing wind force and
how it can be measured is appended. It will be evident that
if a machine capable of flying at a speed of 45 miles per hoiu*
encountered a wind of equal speed and dashed into it, that
the machine would remain practically stationary relative to
the ground and would not advance. A machine with a high
flying speed which calls for considerably more flying speed than
was provided at that time would, of course, be able to make
progress against such a wind.

PLANE FORMS

The effect of using wings or planes of the same area but of
varying shapes and forms is marked, and also with those of
different aspect ratio and aerofoil section, but in tests the
actual results obtained were so much different as to be the cause
of considerable conunent. There is no question but that the
form of the wing of a bird when extended in soaring flight has
proportions which can be followed to advantage by the de-
signer of auplanes; however, the curves of a bird's wings are
not easily duplicated in man-made machines, so that various
forms of aerofoils have been devised that give really good
results when driven through the air at suflScient speed by the
thrust or push . of a propeller. Experiments have demon-
strated that within certain limits the supporting wings should
be long when viewed from the front, and short when seen from
the side. The best proportions have never been definitely
determined and vary in many of the successful creations. The
usual aspect ratio is about 6 or 7 to 1, — that is, the spread of
the wing from tip to tip is 6 or 7 times the depth or width,
measured along the chord.

Professor Langley made some interesting tests to demon-
strate that a plane having a wide advancing edge was the most
efficient. These, of course, were made with small models. A
plane with a width of 6 in. and a length of 18 in. moving

44 The A. B. C. of Ariation

at the rate of 45 miles per hour fell vertically 4 ft. in yio ol
a second. The same plane, when the advancing edge ^^
18 in. and the length was 6 in., has the same supportii^
area as the other and when moving at the same velocity it i^
vertically 4 ft. in two seconds, demonstrating beyond ^
doubt that the sustaining power of the form having the wi^
advancing edge was about three times that of the same pl^^^
when it advanced ^dth the narrow edge first.

Bird and Plane Form Compared. — K one compares tt^
form of a bird with that of some of the late airplanes, as *

German Taube Design

Soaring Bird

IV/'n^ Flap

Wfng^

tievafors

Fuselage

Fmpennaqe

How Airplane Approxima+es Bird Form *rf Viewed from Above

Bird Nosing l/p
iVing^,

r J. ^r u. ' ^Center of
CenferofGravify- Pressure

/^ (

Cenferof
Pressure

Bird in Normal nigh+

Center ofOra vify

Centers of Pressure

Centers oF Pressure

L.\ * Cenier oF Gravity-''

^"^ Movement oF V/i'ngs
A Changes its Posit I'on

Fig. 13. A Bird Can Shift the Relation of Pressure and Gravity Centen by
Wing and Tail Movements and Secure Changes of Direction in a Vertical
Plane with Ease. 1

Fig. 13, it will be apparent that they are somewhat similar in
form, because both have a wide advancing edge or wing spread

Plane Forms

The A. B. C. cf Arialion

Plane Forms

at the plane or wing ia comparatively short, and, as will
dent, the bird can utilize its tail as an auxiliary wing
aids and directs its flight. Corresponding to that it is
ary to provide some form of rudder or auxiliary plane
airplane in the form of an aerofoil which can be Ufted or
sed, so that the air will act on the top or bottom of its
e, depending upon the direction it is desired to fly in,
)ird has no surface that corresponds to the vertical
r necessary on an airplane, because it is possible for it

'Elffvai ng Ruddtrs

X its wings and to flap them simultaneously and thus
i propulsive effort and change the direction at the same
This is not possible with the planes of an airplane
must be immovable relative to the fuselage in order to
! the necessary strength. It is possible, however, to turn
■plane without the use of the vertical rudder by merely
ng the ailerons which would correspond to some degree
e flexing of the bird's wing tips. The vertical rudder is
iary, however, to make good turns in the man-made ma-
even though it can be dispensed with in natxu^'s model.

48 The A. B. C. of Amotion

Airplane Moves in Three Planes. — ^There are really
axes about which an airplane structure can operate, so
three distinct sets of control surfaces are required. In
usual tractor biplane form all of the control planes are at
rear of the fuselage and wings. Those at the tail are called
"empennage." The elevator, which consists of two
capable of moving up and down, is at the extreme rear of
fuselage and controls "pitching" or up-and-down movement
The rudder, which has a vertical surface, is utilized for
turning or "yawing," as it is caUed. The bakncmg or "roll
ing" control, as it is called, is produced by the ailerons or win]
flaps. The main control surfaces are clearly shown at Fig. 11
in their proper relation to the rest of the machine, and a vid
of a typical empennage is shown at Fig. 16. This will h
considered more in detail in a later chapter.

BIRDFLIGHT DIFFICULT TO IMITATE

When one compares the flight of birds with the principk
that underlie the support of an airplane in the air, this is IK
really true, because a part of the supporting force throng
which a bird flies is obtained by the flapping of wings, which .
far has not been successfully imitated by man-made med
anism. It is not strictly a flapping movement, but one tb
combines a flapping with a forward thrust. Another thii
that can never be imitated is the peculiar co-ordination of ti
various body parts by which a bird can chaiige ite j^^ter •
gravity in its relation to the center of pressure and secure i
or do^Ti flight by movement of its head, tail or wings?
comparison between birds and airplanes can only be mai
when one considers soaring birds and then only as long as
supports itself by changing the relation of its wings and bo(
so as to secure the support it needs from varying air currents,-
obviously as soon as the bird starts flapping its wings it ceas
to act in the same way as an airplane, which cannot have ai
relative movement of its supporting surfaces or shift weigh
so that changes of the center of gra\dty may be obtained.

Comparing Airplane and Bird Flight. — In an airplane, tl
fuselage is suspended between wdngs on each side which mi

Birdflight Difficult to Imitate

gle, in pairs or in triplicate, depending on whether the
ne is a monoplane, biplane or triplane. The pr nciple
\ wide advancing edge is made use of — ^just the same as

TABLE III

Wind

From Beaufort Scale of Wind Force

neral

ription

Wind

lir

breeze. . .
breeze. .
ate breeze
freeze. . .

breeze . .

dnd

gale . . .

gale. . .

Specification of Beaufort Scale For
Use on Land Based on Observations
Made at Land Stations

Calm; smoke rises vertically

Direction of wind shown by smoke
drift, but not by wind vanes : . . .

Wind felt on face; leaves rustle;
ordinary vane moved by wind. . .

Leaves and small twigs in constant
motion; wind extends light flag. .

Raises dust and loose paper; smaU
branches are moved

Small trees in leaf begin to sway;
crested wavelets form on inland
waters

Large branches in motion; whist-
ling heard in telegraph wires;
imibreulas used with difficulty

Whole trees in motion; inconven-
ience felt when walking against
wind

Breaks twigs off trees; generally
impedes progress

Slight structural damage occurs
(chimney pots and slates re-
moved) ^

Seldom experienced inland; trees
uprooted; considerable structural
damage occurs

Very rarely experienced; accom-
panied by widespread damage . . .

Mean Wind Force
AT Standard IDbnsity

Mb.

.00
.01
.04
.13
.32

.62

1.1

1.7
2.6

3.7

5.0

6.7
8.1

Lbs. per
Sq. Ft.

.00
.01
.08

.28
.07

1.31

2.3

3.6
5.4

7.7

10.5

14.0

Above

17.0

Equiv-
alent
Velocity
in Miles

per
Hou

our

10
15

35
42

Above

aed in nature's creation. In a bird, which is always a

ly monoplane design, the body is sustained between two

that have sufficient supporting area to perform the

50 The A. Ji. (\ of Aviation

necessary functions during soaring flight, but the control
this is so delicate that by the simple movement of feathers
the wing tips, not necessarily the movement of the wings or
the body, it is possible to decidedly change the poise or balanc
of the bird in the air. Of course, the application of
natural force is instinctive with a bird and the utilizing
speed or wind velocity is all performed automatically withe
materially affecting the progress of the creature. The fact
this instinctive control is not impossible of attainment by
can be shown by the instinctive balancing which obtains when]
one becomes familiar with bicycle riding — the unconsdousj
movement of the body so easily accomplished by the rider wl
has had considerable experience, is very difficult for the novice!
to acquire, and even after s(»veral years' rest it is possible for one!
who is familiar with bicycle riding or w^ho has learned it to get]
on a machine and ride off without any trouble.

Of course the mass of a modern airplane is too great to be
affected by any unconscious movement of the operator, thou^
this principle of leaning the body to secure equilibrium wae
used in early soaring gliders and also in the old control system
of Curtiss machines, where a shoulder rest which could be rocked
from side to side was connected to the ailerons or balancing
flaps. The new system of control, however, does not utilize
movements of the entire body, though an inherent sense of j
equilibrium is absolutely necessarj' in order that the aviator
may tell when his plane is not flying as it should, such as having
one wing lower than the other, or climbing at too steep an an|^e.
When high up in the air, there is nothing to compare this to
except certain parts of the machine, which practice and ob-
ser\^ation tells the operator must occupy a certain position
when in normal flight. We have seen that a slight angle of
inclination is necessar\' to obtain sustentation with the ex-
' penditure of a moderate amount of power and that this angle of
inclination is constantly var>-ing, due to the control elements.
Plane Balancing Principles. — The balancing of a plane is
not difficult to understand if one is familiar with tl\e underlying
principles of simple levers. It is known that the smaller the
distance the weight to be lifted is from the center of support or

Airplane Control Methods 51

fulcrum of the lever, the smaller the amoimt of force that is
necessary to exert a given power. For example : assmne a lever
that had its fulcrum located )i of the distance from the front
end and % from the rear end. If one wished to lift 20 pounds at
the short end, it would be necessary to exert but 5 pounds at the
longer end of the lever to do this, because the power applied
is multiphed by the length of the arm leading to the fulcnmi
point. An airplane may be considered as a lever having the
position of the control surfaces so arranged that the air pressure
on the empennage will produce a lift or depression that will
cause the machine to rock aroimd its supporting point (which
is called the center of gravity) between the wings. The
farther away from the center of gravity the control surfaces
are, the less their area needs be, conversely; the nearer they
are the larger the area must be. This point is briefly touched
upon and will be considered more completely in a later chapter.
Airplane Control Methods. — The control of the airplane is
easily accompUshed by the operator by means of the auxiliary
surfaces which may be disposed horizontally for controlling
movements in a vertical plane, such as the elevator flaps; and
disposed vertically for controlling turning to the right or left
as is the vertical rudder. Horizontal flaps for balancing are
carried at the rear ends 6f the wings to balance the machme.
The manner in which the elevator operates can be readily ascer-
tained by reference to the accompanying illustration (Fig. 17)
which shows three positions of a tractor biplane. The normal
position at A shows the machine flymg along the normal Une
of flight, but the elevator is in a neutral position so that the
air pressure is equal at the top and bottom. This, of course,
produces no movement up or down of the tail. At B the ele-
vator position has been changed so that the air currents lift
under the bottom of the elevator; the resulting air pressure
reaction lifts the tail of the machine up and causes the front
end to nose down. At C the position of the elevator is re-
versed, that is to say, it is incUned in such a way that the air
current presses upon its top surface. This produces pressure,
which tends to force the tail down and lift the nose of the
machine up. The center of gravity of the machine is always

The A. B. C. of Amotion

considered the equilibrium point about which the liftii^ force
at the tail acts. By inclining the elevator up or down we
are able to lift or depress the tail of the machine and produce
a resulting or opposite action at the front end of the machine.
For example: if the tail is forced down, the nose will be forced
up and the machine will climb. If the tail is forced up the noee
will be forced down and the plane will move on a downward

Eltvaforin NtutralAi
Prtaiun Equal Top
andBtlOi

Fig. 17. How the Elevator Controls the Diiectum of ElighL

path. ^Mien the surfaces are left in a neutral position, bo that
the air pressure is equal at the top or bottom, the plane will
fly along the nonnal line of flight.

Use of Vertical Rudder. — The same action that has just
been explained in relation to the elevator will work in about
the same way when the vertical rudder is tilted to the right or
to the left. The reaction of the air against the inclined surface

Use of Vertical Rudder 53

^ naturally pushes the back end of the machine around in the
direction in which the force is acting. In this way it is possible
to steer the airplane in the air just as a boat is steered in the
water. The remaining control, which is that for balancing
the machine or maintaining it in equiUbrium, is obtained by
the wing flaps which are carried at the rear extremities of the
wings in most of the modem machines. (See Fig. 15.) In
some of the earUer airplanes the ailerons were held by the
struts and were carried at a point approximately midway
between the supporting planes. It will be evident that as long
as the wing flaps are allowed to remain in a neutral position
that there will be no more lift on one wing than on the other.
Let us assume that it is possible to raise one wing flap and to
lower the one on the other side, as in banking when making a
turn. The wing flap or aileron on the side that is to be high is
moved so that the pressiu*e will act on its lower surface while
the corresponding member of the wing that is to be lowered is
moved in such a way that the air pressure acts on its upper
siu^ace. The function of the wing flaps or balancing ailerons
is not only to permit the operator to right the machine when
it is tilted by a gust of wind, but also to tilt the machine piu*-
posely when it is desired to bank when the machine leaves a
straight path and describes a circle.

CHAPTER IV

DESIGN AND CONSTRUCTION OF AEROFOILS

How Plane Performance may be Gauged — Meaning of Lift and Drift — Lift-Drift
Value for Rectangular Plane — Meaning of Center of Pressure — ^Properties
of Cambered Aerofoils — ^Leading Edge Should be Curved Down — Best
Design of Cambered Aerofoil — Table 4 — Table 5 — ^Effect of Wing Loading
on Aerofoil Design — Wing Sections Vary in Design — ^Effect of Aerofoil
Camber — ^Effect of Varsring Lower Camber — ^Pressure Distribution on Aero-
foils — ^Position of Maximtun Efficiency — ^Position of Center of Pressure —
What is Meant by Critical Angle or Burble Point— Greatest Lift Produced
by Upper Surface — Table 6.

The reader doubtless wonders how it is possible for an air-
plane designer to determine the best aerofoil form for a given
set of conditions and how it is possible to settle upon a certain
cambered surface as the most desirable. The best proportions
for supporting surfaces can be obtained by experiments with
scale models, which are placed in a wind tunnel and air currents
of varying velocities are forced through the tunnel and around
the model to stimulate the air stream travel of a machine in
flight. If the tests are made with a model of correct pro-
portions the action of much larger bodies of identical propor-
tions can be accurately determined by what is termed the
'^principle of dynamic similarity.'' The practical application
of this is of great value in both marine architecture and aero-
nautical engineering. A prediction of the performance to be
expected from full size airships may be made after wind-tunnel
tests of small models. The wind tunnel is a large rectangular
section conduit having a large power-driven blower type fan
at one end and incorporating suspension and recording devices
by which the action of the model can be observed and measured
by the experimenter outside of the timnel. The blower fan
can be driven at different speeds and air currents varied to

simulate winds of various velocities.

Design and Construction of Aerofoils

The A. B. C. of Aviation

HOW yULS^E. PEETOEMANCE MAT BE GArGED

lu tlifr caw* where lite Tiesi of & mcKki. winch may be either
ati airpiaiit or any of the pan? of which n k tompaseAj is
luude iii the air stream of the same TeJodty in wh'ch the full
tsiaied ma'.iLiiie or part is to move, the foroes upon the small
and full >ia*5d bodier "wtU be proportional t<i the square of their
oorr*?6poiidiLi^ d ineiL-don* and als«j t-c* the square of their
r»:?iati\'e \'^lw\if± if the air -rrream acting on the model is less
thai- the wind pre?!irPjre that will act on the full sized body.
hy blowjnjj wmoke in the wind ttmneL the actual flow lines of
the air aroujid the bodv mav be determined visually and, if
j/h</V.^graph^, made a matter of permanent recoid.

MEAXIXG or UFT AXD DRIFT

^>^n><idering fir??t a flat plane, when this is tipped so it
j/iai**f an arrut-e angle with the relative wind, it will be sub-
j*5^,-t^i t/> the forc<5S Aiown at Fig. 19. The vertical force which

• Forc9

Anqft of
fncicf0nc€

Drag\ Component

Dtr§cfton of Relative Wind

Flaf Plane

Fig, f Q. Diagram Showing Meaning of Lift and Drag, and Forces Represented

by These Terms

irt /' (!()Hin(i angle of inclination is called the "lift" component^
and \\\i\ horizontal force, which is indicated as P sine angle of
inclination is termed the ''drag" or ''drift" and offers a resist-

Lift-Drift Value for Rectangular Plane

ance to forward movement of the plane. The pressure P is a
resultant of the two component forces. Obviously, it will be
desirable to have the " lift " component greater than the "drift "
or "drag" component and the greater the difference between
the two, the more effective the lifting abiUty of the plane be-
comes, because the lift is increased and the resistance to forward
motion or "drift" is reduced. The value of the "lift-drift"
ratio for an inclined flat plane will depend upon the inclination
and aspect ratio of the plane, the latter not influencing this
much above aspect ratios of 8 or 10. ^Aspect ratio means the
relation between the length and breadth of the plane^ For
instance, a rectangular plane with a length of 20 feet and a
breadth of 4 feet would have an aspect ratio of five.

LIFT-DRIFT VALUE FOR RECTANGULAR PLANE

The results of a wind tunnel test to determine the lift-drift
values for different angles of inclination upon a rectangular

0.70

«, 0.60

-»-
c

•5 0.50

it
A ^Aerofoil (Lift) J 0.40

B' Plane (Lift) "^
C' Plane (Drift) jt qjq
D'Drrff (Aerofoil) q

c 0.20

% 0.10
OO

C
D

'^x*^

3 5 10 15 2
ngles of Incidence
( Degrees)

Fig. 20* Diagram Showing Lift and Drift Values for Flat and Cambered Planes.

plane scaling 12.5 inches advancing edge by 2.5 inches chord
are shown graphically in Fig. 20. The wind velocity was 20
miles per hoiu*. The lift force follows a linear law of variation

The A. B. C. of Aidation

up to an angle of about 15 degrees and the lift reaches its
maximum value at about 20 degrees. The "drift" eoeflScient
varies slightly between and 4 degrees, from which point it
increases rapidly following a parabolic curve. If these curves
are compared with similar values for a cambered aerofoil
plotted in the same chart, we find that the lift curve of the
aerofoil reaches its maximum at about 16 to 17 degrees angle
of incidence, after which the lift falls sharply. This angle is
termed the critical angle or ''burble point " and is the maximum
angle of incidence for the aerofoil in question because any
further increase decreases the ''lift" and greatly augments the
"drift," and as these cur\T.s tend to meet, the lifting ability
of the aerofoil diminishes.

MEANING OF CENTER OF PRESSURE

The "center of pressure" of any aerofoil or body exposed
to the wind may bo (considered as the point where the resultant
force shown at Fig. 19 acts. In the case of a flat plane normal

< bpan

'• Entering Cdgm

' ,' Tra II in g Eclg e

\ Acfual Line of Centers of Pressures
^^Supposed Line of Centers of Pressures

Fig. 21. Location of Centers of Pressure on a Rectaagakr AerofoiL

to the wind direction the geometrical center may also be coJJ'
sidered the center of pressure. The "center of pressure" posi-
tion is an important consideration in aerofoil design becaii^
the computations for the strength of wing parts are of necessity

Properties of Cambered Aerofoils 59

ased on the position of the center of pressure which represents
ae load. The initial center of pressiu-e movement is greatest
1 aerofoils of large aspect ratio, and in flat rectangular aeio-
oils, the center of pressiu*e will be at the center of the aerofoil
it 90 degree inclination. It does not follow, however, that
the center of pressures of all the aerofoil sections will be the
same distance from the leading edge. In fact the C.P. of -the
central part of the plane is nearer the leading edge, while the
CP.'s of the portions near the extremities are nearer the
trailing edge. This is clearly shown in Fig. 21. The travel of
the center of pressure is greatest for small incUnations, and it
is nearest the leading edge where plane is tilted at small angles
rf incidence. The reason the center of pressm'e is nearer the
raiUng edge as it nears the extremities of the plane is because
'f ''end losses." This is caused by the ingress of air at at-
iosphere pressure into the region of partial vacuima above
Qd also because of the flowing of the air under pressure below
^e plane into the air* not acted upon by the plane movement.
tus results in a reduction of ^'liff and an increase in ''drag"
1* the sections near the wing or plane tips.

Properties of Cambered Aerofoils. — While previous con-
ieration has been of flat planes, it is necessary to consider
^ cambered aerofoils ordinarily used in airplanes as these
t'^ve properties that make them more suitable for sustentation
a,n flat planes. The wings of birds are really cm^ed or cam-
'X'ed in section and unless there was some advantage in this
^thod of forming wings, it is evident that Nature would have
»^ the simpler flat plane. Both theory and practice indicate
-€it there are marked advantages in having airplane sup-
>rting members of cambered section. Comparison of the
^tion of air currents when meeting flat and cambered planes
lay be made by referring to diagrams at Fig. 22. Considering
ie flat plane shown at A, which is supposed to be dropped
ertically, it will be evident that owing to the compression
elow the plane and the rarefaction of the air above it that
liere is bound to be a circulation of air from below the plane
3 the less dense area above it, this giving rise to a kind of
ortex motion. Then consider the action of the flat plane

The A. B. C. of Aviation

moving in a horizontal direction as shown at B. Here, atsQ^I ^
we will have a vortex action and the leading edge of the pi
will meet air having a relative upward velocity and the lea(
edge cannot meet the air in the most efficient manner as ihm\
will be considerable shock and resistance to forward moticHL

I ' r-

\ \ ^r;

' v^.-*/'

Fig. 22. Diagrams Showing Advantages of Cambered Section AerofoiL

The " drift " curve is of lower value for a cambered aerofoil than
it is for a plane as shown graphically in Fig. 20.

Leading Edge Should Be Curved Down. — ^To meet the air
without shock it is important that the leading edge be curved
dowTi so it will approximate the direction of the air currents
meeting it as showTi at Fig. 22 C, and the shape of the aerofofl
bo such that it can be considered as an element of a body rf
good streamline form. As will be seen by reference to Fig. 23,
the air stream travel is such that it is at first upwards, then
finally downward, so in the case where the aerofoil is moving
horizontally and inclined at a moderate angle of incidence
having a low **drag" or **drift'' value to retard its forward
movomout, that a downward momentum will be ^ven to
air st roams, this resulting in a vortical lift.

Best Design of Cambered Aerofoil

Best Design of Cambered Aerofoil. — The air streams
flowing over the top of the aerofoil are deflected sharply up-

rArea of Reduced
Pressure

Enier/ng.^,^
Edge

Trailing Edge

Fig. 23. Diagram Showing How Vertical Lift Is Obtained on Cambered Aero^

foil Because of Air Pressure.

wards and as a result, there is an area of reduced pressure
above the top camber of the aerofoil which augments the value
of the lifting force by reducing the pressure of the air above it

R.A.F. No. 5 Aerofoil Sec+ion

Wing Sec+ion of Dusky Horned Owl

R.A.F. No. 3 Aerofoil Secfion

Ulna.

Radius-^

Wing Sec+ion of Herring Gull
^Tensor Paiagii Longus .

^ig. ^. How Bird's Wing Section Compares With Aerofoil Sections.

■2

The A. B. C. of Ariatwn

j^ eoDsequeucly the resistance to the upward movement of
■ ^ :ierofoiI. The real advantage of a cambered aerofoil
l^^ieatly is that it receives a current of air in an upward
'^^^•tioa and directs it downward, thus obtaining a lift reactioo.
-^^ best desgji of cambered aerofoil would be the form that
^1 zbn Hjeatest area of n^ative pressure on top and the
^,j^t*wt value of positive pressure on the bottom and that at

*»»*4vlv« xitwlw* vl AkptaM Wtoj Showing Cwnbered Ribs Which
*^ ^* Vm* Uk* AmuIoO Its Shape.

O .n.i.' uiiu' w*^ «*' toiiuwi that there would be no break or
UK «" vUi' ..limmldH- air tU»w ww its surfaces.

iv^rtvWiti va W^IV Wtai*». In the preceding chapter men-

tii Ht ■ «"•«'«• <'' *'*^' wuulavit.v m cri>ss-section of some of the

. r,h.il- " '■>' »" ■*»' !'>»"»' ""lUHTt and the wings of birds.

X\v ti.^v lHk«l»»tt *'l ''"^*'*' '■•■■• '***• anwunt of wdght carried'

! „"n ■.•»■* 1' lm>»i v\«ui>»mi to that of flying machines as

a ,.i. ■ iM»t" >"*>* ■* l"*'""** '*' - P«"°<^ per square foot.

1*4^ l.ttt "I '» l'''**''^ \vilmw\ for instance, are loaded 1.25

" ((f.mi^m'twV IVwwtwmng members of the dusky

Loading of Bird's Wings 63

homed owl and the tawny eagle are loaded about 0.90 pounds
per square foot. All birds' wing sections are different and
undoubtedly have, changed in form as a result of a natural de-
velopment or evolution depending upon the habits of the birds,
such as whether they were gUders, soarers, flappers or swimmers.
The student of airplanes may wonder what the proportions
of the flying machine devised by nature are and how the sup-
porting surfaces compare in different birds in reference to then-
weight and flying power. It is conceded that while a study of
bird flight and form may be of interest to the student, it is
hardly necessary to give this more than passing consideration
at the present time. It has been stated that in pre-historic
times much larger creatures inhatfited this earth than we
know of to-day. These included peculiar flying forms that
were neither bird, reptile or mammal, but which had char-
acteristics of all of these. Many centuries ago a large flying
creature which was a combination of reptile and bu-d and
which was known as th^ Pterodactyl existed, and while it is
not possible to give the exact size of this creature, from the
present existing skeletons reconstructed by modem scientists,
it is assumed that the wing spread was about 20 feet and that
a supporting area of about 25 square feet was available for
supporting it in flight. The weight was 30 pounds and it
was estimated that it was capable of exerting about %5 H.P.
If we consider the modern bkds, perhaps the largest soaring
biped is the condor, which has a wmg stretch of 10 ft. from
tip to tip, a weight of 17 pounds, a wing area of about
10 sq. ft. and which is capable of exerting about /so H.P.
The tiu*key buzzard is a smaller soaring bird which has
a wing stretch of 6 ft., a supporting area of 5 sq. ft., a weight of
5 pounds and a power capacity of but little over /loo H.P. It
will be evident that the ratio of supporting surface to the weight
of the creatures does not always vary directly with their weight
and^ strange to say, the larger the creatiu*e the less relative power
and surface area is needed for its support. The following table,
which deals with insects, is given to support this contention. In
this, as a basis of comparison, each insect is supposed to be
proportioned so that it will weigh 1 pound. Insects fly by

The A. B. C. of Aviation

very rapid vibration of their wings and seldom soar. The
figures given were pubhshed as early as 1868.

TABLE IV
Squabe Feet Wixg Area per Pound Weight

Ineerta

Wing Am

Gnat

49.0

Dragon Fly

30.0

Bee

5.25

Flies

5.1

Stae-Beetle

3.75

Bhinocerous-Beetle

3.14

This table serves to prove the law that the larger the
creature the less the relative area of support to a given weight
holds true as applies to insects, and as we shall demonstrate
by the following table, which has been prepared from data

TABLE V
Value op Nature's and Man's Flyixg' Machines

Birds

Humming bird

Pigeon

Wild goose

Buzzard

Condor

Pterodactyl

Airplanes

Bleriot XI (early
monoplane)

Wright (early bi-
plane;)

Curtiss (early bi-
j)lan(0

Standard Model J
(mo<lem)

Wright-Martin Mod-
el V (modem) ....

BurgciHH Ty\xi V Sea-
pliiiic Cniodern) . . .

Weight
in Lbs.

0.015

Surface
In Sq. Ft.

H.P.

Area
per Lb.

H.P.
per Lb.

•

0.026

0.001

1.73

0.066

1.00

0.7

0.012

0.7

0.012

9.00

2.65

0.026

0.2833

0.00288

5.00

5.3

0.015

1.06

0.003

17.00

9.85

0.043

0.57

0.0025

30.00

25.00

0.036

0.833"

0.0012

700.00

150.00

25.00

0.214

0.035

1,100.00

538.00

25.00

0.489

0.022

700.00

258.00

60.00

0.368

0.85

1,350.00

429.00

100.00

0.318

0.014

1,725.00

430.00

150.00

0.24

0.092

1.800.00

500.00

100.00

0.27

0.55

Lbs.
per Sq.

Surface

4.7

2.04

2.7

3.1

4.01

3.6

Note — Airplane weights given without passengers or military loads.

Effect of Wing Loading on Aerofoil Design 65

compiled by Langley, which has reference to both soaring birds
and those which fly by flappmg their wings it will be evident
that the law mentioned holds true for large living creatiu*es.
Birds, such as the pigeon and goose, seldom soar, and they must
keep flapping their wings practically all the time they are in
flight. The humming bird flies by moving its wings rapidly
so that its flight resembles that of an insect more than it does
of a bird. The larger creatiu*es enumerated are soaring birds
and it is to these that the aeroplanes should be compared.
The figures given are only approximate, but are of interest
in showing the proportions obtained in both natural and
man-made flying machines.

Effect of Wing Loading on Aerofoil Design. — ^The wing
loading of early airplanes was seldom more than 3 pounds
per square foot and in the case of the early Wright machine

« 30 >k 30 >l« 30-

7^/////^y^yj/y/>^/»//y^//y

-7.es sji

-^ ZO 3

>k — 30

>"J.^

Fig. 26. Aerofoil Section of Early J'orm Suitable for Light Loading.

it was but little more than 2 poimds per square foot. At
the present tune wing loadmg has mcreased to 5 or 6
poimds per square foot average and in some very high-powered
fast airplanes it may run up to 10 or more pounds. in rare
instances. A wing section to carry a heavy load must be a
deep section. The section shown at Fig. 26 gives the approx- "
imate proportions of the early Wright aerofoil which was
lightly loaded, and its shallowness will be apparent. The
diagram at Fig. 27 shows the deeper section needed for struc-
tural strength and to accommodate spars of the proper cross-
section to withstand the increased load.

It will be evident, therefore, that structural strength, as
well as aerodynamical considerations, must be taken into ac-

The A. B. C. of Aviation

count in selecting aerofoil sections. The factor of strength
ma^ be considered fully as much as efficiency, and if a com-
|nx>mise design must be evolved where one or the other of these
qualities must be sacrificed, it is better to favor strength even
if the efficiency is somewhat less. Many forms of wing sections
have been developed. Some have attained one object, others
have properties that make them suitable for other work.
There is no one vfing section that is the best: Efficient forms
devised for speed craft are not suited for slow flying or weight
canying planes. The best aerofoil section to use depends
entirely upon the use to which it is to be put. Any fixed aero-
foil section is suited to only a limited range of flying angles, and

''^' ^jfz^ — 1» fr U — <

ta.s

— >k~/5 -^4<-/5'->K-/5-

i r* It tL

I 0.0

<—

IS9

Pig. 27. Aerofoil Section of Modem Airplane Suitable for Heavy Loading.

the present construction of a tilted aerofoil of fixed cross-
section is by no means the best, if one looks at it from a theo-
retical point of view, though it is a compromise that gives
adequate results in practice. To secure the best results from*
an aerofoil as regards lift, drift or resistance and center of
pressure position, the section of the aerofoil should be changed
with every alteration of flying speed. This is a theoretical
consideration that is difficult to meet in practice, owing to
structural difficulties. Inasmuch as a practical variable
camber wing has not yet been designed, the fixed aerofoil
section to be selected depends upon the type of plane and the
work it is expected to do.

Wing Sections Vary in Design. — ^Various wing sections
intended for widely differing types of machines are shown at

Wing Sections Vary in Design

Fig. 28. That at A is intended for a fast scout plane and while
the section is a good streamline form, the hft is so small at
moderate speeds that it can be used only on very fast flying
planes. The same applies to the aerofoil shown at jB, which
has a reverse curvature at the traihng edge. This wing has
good aerodynamical properties because the center of pressure
travel is small, but as its lifting power is low compared to the

Aerofoil Section -for Fast Plane

Aerofoil Section for Medium Speed Plane

R.A.F. 6 Aerofoil Section for Training Plane

r«.

Fig. a8« A and B, Aerofoil Sections for Fast Planes. C, Aerofoil Section for
Medium Speed Plane. D, R. A. F. 6 Aerofoil Section ipr Training Plane.

sections shown at C and D, can be used to advantage only on
speedy machines. Wings of the forms shown at C and D
are used on medimn speed biplanes. The landing speed of a
small plane having wings of the section shown at A and B
would be about 50 miles per hour, and would call for very
skilful piloting. The other wing section at C and D are
suited for medium speed biplanes, as they would permit a
landing speed of about 30 miles per hour. The maximum

The A. B. C. of Aviation

speed of a properly powered plane using wing sections A or £
may attain values of over 100 miles per hour, that of sections C
and D would not be much more than 65 or 75 miles per hour.
In order to illustrate how widely the requirements differ
and the types of aerofoils best adapted for use under different
conditions of airplane operation, the sections at Fig. 29 are

Fig. 29* Aerofoil Sections Desdgned for Special Work, Showing How Widd^

They Differ.

given. These are reproduced from A. W. Judge's treatise,
''The Properties of Aerofoils and Aerodynamic Bodies," and
show ideal wing sections.

The wing form required to secure the highest lift with the
most efficiency is shown at A. Such an aerofoil would be

vr.

Effect of Aerofoil Camber 69

suitable only for a low-speed machine, as it would offer a high

head resistance even at small angles of incidence. It would

be a good form for slow flying machines but very inefficient

. for high-speed types. The section at B is typical of aerofoils

intended for medium flying speeds and at the same time secure

a fairly low landing speed. An aerofoil of this type could be

utilized for a machine having a flying range between 35 and

65 miles per hour. The wing at C shows a section

developed to obtain a high lift-drift ratio at small angles

of mcidence, and while a machine equipped with aerofoils of

this section would not have a very low aUghting speed, it

could attain fairly high flying speeds as the range would be

from 55 to 100 miles per hour. The wing section at D is a

peculiar aerofoil designed for very high speeds. It would be

entirely imsuited for low-speed work and is to be used only on

inachines of very high power. The landing speed would be

Very high as the angle of incidence is negligible in normal

flight.

EFFECT OF AEROFOIL CAMBER

Both upper and lower cambers of an aerofoil have material
^^uence on the aerodynamical properties. Very complete
^^Periments have been made to determine both the upper and

Max. Ord.^.^
k^

■* ^40

\ ci

May, Ord in ate •''

Max. Ord.""''

^^* 30. Wing Sections Experimented with to Determine Value of Top Camber

^ower cambers, and considerable data is available for the

student. It is not within the province of a discussion of this

^aaracter to go deeply into the theory of form and proportions,

"^t it may interest the reader to consider typical designs in

70 The A. B. C. of Aviation

both cases and study the values determined for each form.
For example, a range of sizes of which the forms shown at
Fig. 30 are examples were tested, all having a flat lower sur-
face but with upper surfaces of varying convexity and depth of
section. The figures in the illustration show the proportions
the maximmn ordinate bears to the chord. The position of
the maximmn ordinate was the same in each case, or about
0.292 of the chord from the leading edge. It is found that the
thicker the aerofoil the greater the Uft coeflScient at small
angles of incidence. This is undoubtedly due to a greater
total deflection of the air. The thin aerofoil at A starts to
lift at minus or 1 degree of incidence, but the thick section
at C starts to lift at minus 7 degrees angle. At degrees
angle of incidence the values of the lift coefficient are pro-
portional to the depth of sections. The section best adapted
for a wing is one that has a top camber that is an average
between the form shown at A and B, the depth of the camber
being about %o the chord length. The camber shown at
C is used only in propellers, and then only where strength is
desired, as neay the hub. It would have too much resistance
to be used for a wing section.

:effect of varying lower camber

In order to determine the influence of various lower cambers,
a series of aerofoils were made with various degrees of con-
cavity. A series of tests were made with four aerofoils having
sections as outlined at Fig. 31. The deduction that can be
made from the data shows that the under-camber influence is
to increase the lift at all angles and even at small angles the
percentage increase is considerable. The form at D has the
greatest Uft coefficient value. At zero angle of incidence the
form at B has 13.9 per cent, increase over A ; C has 24.2 per
cent., and D has 33.3 per cent, increase over the form with the
flat under-surface. The upper camber was the same in all
cases. At 6 degrees angle of incidence the percentage increase
varies as follows: B, 4.9 per cent.; C, 8.2 per cent.;/), 12.9
per cent. At 10 degrees angle of incidence the form at B

Pressure Distribution on Aerofoils 71

W 2.8 per cent, increase; C, 7.3 per cent, increase, and Z),11.2
per cent, increase.

It is therefore evident that the best form for securing
maximum hft at low speed will have both upper and lower
surface cambers pronounced. A sharp leading edge is not as
good as a slightly rounding one. The wing sections of birds
show a fine tail angle and have considerable under camber as

Flat Lower
Surface

y77//////////A

^S* 31. Wing Sections Experimented with to Determine Value of Various

Bottom Cambers.

^^U as a pronounced upper camber and a rounded entering
^dge. It is possible to obtain 10 to 15 per cent, more lift at
high angles of incidence by using a fine tail angle and a good
Under camber. For high-speed work it is evident that aero-
foils having a good upper camber but a nearly flat lower camber
or forms having two convex surfaces as shown at Fig. 29, C
and Z) will be most suitable.

Pressure Distribution on Aerofoils. — Consideration has
previously been given to the various aerofoil sections and

The A. B. C. of Ariaiion

diagrams have been presented showing the supposed air flow
about the cambered sections so that a definite lift could be
obtained both from the positive pressure existing below the
plane and the n^ative pressure existing above it. It is fq>-

Fig. 31. Graphic Diagiams Showing Pressure Distribution on Top and Low«
Surfaces of a Cambered Aerofoil at Varying Degrees of InclinatkKi.

parent that the greater part of the lift at normal angles of
inci(l(!iice is secured by the negative pressure and that this is
always greater than the positive pressure below the plane
resardlcss of angle of incidence. Pressure observations have

Position of Maximum Efficiency 73

been made by Eiffel and others with aerofoils of varying cross-
sections and while numerous interesting deductions could be
made by studying the entire series of tests, in a discussion of this
character it is only necessary to study typical diagrams which
show graphically the pressure distribution.

Referring to Fig. 32 a deep cambered wing section is shown
at A that has no perceptible angle of incidence. The pressm'e
distribution is represented graphically by normals drawn
from both upper and lower surfaces of the aerofoil and having
the degree of pressure existing indicated by making the length
of the lines proportional to the existing pressure. The positive
lift is denoted by normals drawn from the lower surface down,
while the negative pressm'e or suction hft is indicated by lines
drawn normal to the upper cambered surface. It will be
evident that at zero angle of incidence all of the Ufting force
present on the wing is produced by the negative pressure or
suction lift above the cambered surface. There is a certain
amount of negative pressure on the underside of the aerofoil
at the entering edge which actually detracts from the eflSciency
by reducing the Uft. It will be apparent that in the wing of
a fast airplane, the top surface should be so designed as to
carry practically all of the load. The aerofoil tested had an
aspect ratio of six and the tests were made at a wind speed
of a mile per minute, or 60 miles per hour, which would cor-
respond to a normal flying speed for an aeroplane havmg deeply
cambered wing section and only moderate power.

POSITION OF MAXIMUM EFFICIENCY

The maximmn efficiency of the aerofoil was obtained with
the wing at the position shown at Fig. 32 B in which the
angle of mcidence is 4 degrees as, while the hft is not as great
as it is at a higher angle of incidence, it is at this position that
the greatest lift is obtained with the least resistance. It will
be observed that there is more uniform distribution of pressure
upon both upper and lower surfaces, and while the value of the
negative pressure is of considerably greater amount than that
of the positive Uft, both of these attain their greatest value but
a short distance from the leading edge. At 12 degrees inclina-

74 The A. B. C. of Aviation

tion, which can be considered the position of TnaximiiTn lift,
the great increase in the negative pressure eflfect near the
leading edge at this angle of incidence is easily noticed; also
the progressive faUing off toward the trailing edge.

POSITION OF CENTER OF PRESSURE

From these graphic diagrams it will be evident that it is
because of the greater magnitude of both positive and negative
pressure effects near the leading edge that the center of pressure
is nearer to the leading edge than to the center of the aerofoil
section at ordinary angles of flight. While the position of the
center of pressure varies, it may be stated to average about
one-third of the length of the cord from the leading edge.
With a certain aerofoil section the pressure upon the upper
surface near the leading edge at an angle of inclination of 10
degrees and with a wind speed of a mile per minute is about
40 pounds per sq. ft., while near the trailing edge it is about
3 poimds per sq. ft. only, which makes the average lifting
force for the whole surface about 10 pounds per sq. ft.

WHAT IS MEANT BY CRITICAL ANGLE OR BURBLE POINT

If an aerofoil is tilted from incidence, the values of the
suction lift ca^egative pressure on the top camber continually
increase until a certain angle is reached which invariably lies
between 14 degrees and 20 degrees, where a pronounced change
in the values of the pressures occurs and where a further in-
crease results in a practically uniform and reduced lift. This
is called 'Hhe critical angle" because, as has been previously
shown, the value of the lift coefficient becomes suddenly
reduced, while the drift coefficient, which is a measure of
resistance, increases greatly. The sudden change in the
pressure distribution is sometimes called 'Hhe burble point"
and is evidently due to a sudden alteration of the air flow ovct
the camber of the top surface of the aerofoil, and air flow in
which there are so many eddy currents that there is a dead air
region which offers resistance Avithout producing any useful
lifting effort.

Greatest Lift Produced by Upper Surface 15

Greatest Lift Produced by Upper Surface. — It will require
but brief study of the graphic pressure diagram given at
Fig. 32 to ascertain that of the total Ufting force on a cambered
surface aerofoil that the greatest Ufting effect is due to the
negative pressure or suction Uft on the upper surface. The
amount of this hf t will vary with the section of the aerofoil, and
it may be stated to range from 75 per cent, in the case of a flat
plane to as high as 92 per cent, in the case of a cambered plane
at zero angle of incidence. In the case of aerofoils having a
fairly flat lower surface, the upper surface at degrees incidence
practically supports the load. At 4 degrees the lower surface
contributes but 18 per cent, of the lifting effect. Aerofoils
designed for fast flying are of such form that the upper surface
contributes from 95 to 100 per cent, of the total Uft while in
cambered sections designed for slower-speed machines the
upper surface is responsible for from 65 to 85 per cent, of the
lifting influence. The following table shows the percentage of
the total load carried by both surfaces in an aerofoil having a
fairly high total Uft.

TABLE VI

Percentage

OF Total Load Ca

RRIED

Ang^e of Inddenoe.

Lower Surface.

Upper Surface.

degrees

CHAPTER V

ARRANGEMENT, CONSTRUCTION AND BRACING OF

AIRPLANE WINGS

Monoplane or Biplane — Effect of Gap — Table 7 — ^Effect of Stagger— PlaJi©
Forms — Securing Uniform Pressure Distribution — ^Airplane Wing Cost"
struction — ^Wing Covering Fabric — ^Why " Dope" is Used for Wings— Ho^'
Fabric is Fastened — ^Airplane Wing Bracing — ^Loads on Airplane Wing Wires
— ^Airplane Wing Form — ^Planes with Longitudinal Dihedral — Influence ci
Lateral Dihedral — ^Airplane Wing Bracing — Side Bracing of Airplane YHngfr—
Airplane Bracing Wires — ^Typical Wire Bracing Arrangements

MONOPLANE OR BIPLANE

The latest developments in airplane construction have
resulted in such a great increase of efl&ciency for the biplane
type that it is now practically universally used. In the early
days the monoplane was the type used for carrying light loads
at high speeds while the biplane was .the form favored for
carrying heavy loads at relatively slower speed. The biplane
is undoubtedly the form having the greatest structural
strength as well as permitting one to obtain the greatest amount
of carrying surface in the most compact form. For example,
if we consider a biplane having 40 ft. spread with a 6 ft.
chord we have planes having a surface of 240 sq. ft. each
or a total of 480 sq. ft. for the two planes. If one desired
to obtain this same area in a monoplane and did not wish to
depart from an efficient aspect ratio it would be necessary
to use a single plane having a 60 ft. spread and an 8 ft.
chord. It will be apparent that the design of a wing structure
of these dimensions would be somewhat of a problem and it
would require a high grade of engineering to have a strong
wing skeleton which would be properly braced without making
the framework too heavy.

As the weight that can be sustained with a given amount
of power depends largely upon the area of the useful Supporting

76 .

Effect of Gap 77

surface and the velocity of the plane through the an*, it is

evident that if one decreases the supporting surface that one

lessens the carrying abiUty. Of course, if more power is

provided and higher speeds obtained the wing loadings can be

increased from the average value of 3 or 4 pounds per sq.

ft. to twice that amount, but this can be secured only

by the sacrifice in low landing speed. The real reason why

the monoplane was favored in the early days was because

plane forms and their proper relation had not been as carefully

studied as they have been in recent years. It was found

that the efficiency of a surface was reduced if other planes

were carried near it. It was therefore necessary to correct

monoplane values to allow for the biplane arrangement.

EFFECT OF GAP

The results of wind tmmel tests upon exactly similar aero-
foils arranged one above the other shows that there is a disad-
vantageous interference due to conflicting air currents between
; the two planes unless there is a gap between the planes of at
least twice the chord. If the gap between the planes is less
than this figure there is a reduction in the lift effect of the two
planes. The condition can be easily imderstood if one refers
to the diagram at Fig. 33 A, which shows two planes separated
by a distance equal to only half of the chord. It will be evi-
dent that there is a large area of disturbed air between the
two planes. This results in a reduction of the positive lift
on the upper plane and of the negative lift on the lower one.
We then have two surfaces working at greatly reduced efficiency
^d we are depending upon the efficient upper surface of the
top aerofoil and the efficient lower surface of the lower aerofoil.
The diagram at Fig. 33 B shows the planes separated by a
distance equal to the length of the chord. This is the usual
spacing and while it is not the most efficient one it is the dis-
tance commonly used on account of structural reasons. There
^ still an opportimity for a conffict of the air cmrents between
the surfaces but the area of disturbed air is considerably less
than in the case where the gap was equal to but half the chord.
When the gap between the planes is equal to the chord a bi-

78 Tb£ A. B. a of Aviatum

plane has an efficiency of but 80 per cent, of a monoplane of the
5-anie ■nnng area and aerofoil section.

^E- 33- Dlagruns Showing Effect of Biplane Spacing. A. WItfa gap equal to
half the chord, note interference and eddies. B. "WHi gap eqvuu to diord.
C. Effect of staggering aerofoils.

It will be seen from the following table that the gaps tried
varied progressively from 0.4 to 1.6 of the chord. The coeffi-
cients given are values by which the monoplane lift coefficients
have to be multiphed in order to secure the biplane spacing
values for the gaps given. The wing tested was the form used
on the Bleriot-XI, of a plan form that had a rounding wii^ tip
and a shorter trailing edge than entering edge. The spread
was about five times the chord. From the table it will bo
evident that the best arrangement or spacing of the biplane

Effect of Stagger

wings is determined by practical considerations. While there
is an increase in eflSciency as the gap increases there is a corre-
spondmg mcrease in the length and consequently the resistance
of the plane spacmg struts, the hf ting and landmg bracmg wnes
and also the incidence wires. Practical considerations generally
limit the gap or spacing so that it seldom exceeds the chord.

TABLE VII
Corrections for Biplane Spacing

Ratio Gap

Lift Coefficient

Chord

6 Degrees

8 Degrees

10 Degrees

0.4

0.61

0.62

0.63

0.8

0.76

0.77

0.78

1.0

0.81

0.82

1.2

0.86

0.87

1.6

0.89

0.90

EFFECT OF STAGGER

The eflSciency of the biplane arrangement can be increased
by staggering the planes, i.e., setting the entering edge of one
plane some distance ahead of the entering edge of the other.
A somewhat exaggerated stagger is shown at Fig. 33 C The
effect of moving the top plane forward is to increase the lift
coeflScient as well as obtaining a higher value of the lift-drift
ratio. When the top plane is moved forward a distance equal
to about two-fifths of the chord an increase in both hft and
lift-drift coefficient of about 5 per cent, is secured. This is
equivalent to increasing the gap from 1.0 to 1.25 of the chord.
Staggering the planes improves the efl&ciency of the upper
plane because it reduces greatly the disturbed area between
the planes. The planes are not always staggered forward;
sometimes the lower plane may be set ahead of the upper one.
The best effect is obtained by using the positive stagger rather
than the negative as the range of vision of the occupants of
the airplane is much better when the top plane is staggered
forward and a more decided gain in efficiency is obtained.
The views at Fig. 34 show two types of tractor biplanes. That
at A shows a standard training machine which has a positive

80 The A. B. C. of Aviation

or front staler, in this the upper plane is set forward of the
lower plane. The design shown at B has a slight negative stag-
ger as the lower plane is set somewhat ahead of the upper one.
Plane Fonns.^It is not the purpose of a popular discussion
of this character to consider the technical aspects of pressure

Vig. 34. Topical Tractor Biplanes of Modem Design Showing PositiTe «
Forward Stagger at A and Negative or Bade Staler at B.

distribution over the entire surface of the wings, but enoi^
has been presented in a preceding consideration of this subject
to show that the pressure is not uniform at all points on the
wing. While considerable useful information may be seciu^
if careful thought is given to the variations in pressiu« along
the leading edge of the wing and at some distance back of this
hue on both upper and lower surfaces, experiments have shown
that the values of the positive and suction hft over the central
portion of the aerofoil or those parts near the fuselage were
greater than at other portions of the wing and that the values of
the positive and negative pressure became less near the wing tips.

Plane Forms

The reason for this is that the air that is under pressure
A that part of the wing near the tips has nothing to restrain
ts flowing out sideways and inasmuch as this escape of air
over the edges produces eddy currents, the value of the suction
lift at the top will be likewise reduced. The reason that wings
of reasonably high aspect ratio are more efficient than those
fonns of low aspect ratio is that the relative magnitude of the
in Uft due to the escape of air will be less in proportion to

Leas+ E-fficien+ Plane

Albatross
Efficient Plan Form of Soari'ng Bird

^g 35. Diagram Showing Efficient Wing Plan and How It Approximates Bird

Wing Plan Form to Some Extent.

lie total surface on a wing of large span and small chord than
i will be on an aerofoil of short span and long chord having
\ie same area. This means that there is a gradual movement
f the center of pressure from the leading to the trailing edge
f the wing, the center of pressure being nearer the leading
dge at the central point of the wing and nearer the trailing
dge at the wing tips.
The early forms of planes were built of a rectangular plan

The A. B. C. of Aviation

form as shown at Fig. 35 B. This was done because the influ-
ence of plan form on efficiency was not clearly defined and
because it was a very easy form of wing to build, calling for a
very simple framework, and, in fact, the single surface aero-
foils of early days were not adapted to use the wing frame
skeletons that are now available since the double surface aero-
foils became universally used. The rectangular plan form is
less efficient aerodynamically than the later forms even on
those lyings having a high aspect ratio. The form of wing
shown at Fig. 35 A is more efficient than the simpler rect-
angular form shown below it, as this gives an increase in total
eflfective lift with a marked reduction in resistance or drift and

*' Leading £'dge

Bleriot Wing Plan D
^Leading Edge

German Tonite Wing Plan ^

Fig. 36. Theoretical Plane Forms to Secure Uniform Pressure Distribotioa

at A, B, and C. Actual Plane Forms at D and S.

at the same time there is no sacrifice of any of the construc-
tional features making for strength stability or ease of
building.

Securing Uniform Pressure Distribution. — ^In order to
secure a reasonably imif orm pressure distribution it has been
stated that an ideal plan form would be one consisting of two
triangles having their bases joined at the central section, the
apex of each triangle representing a wing tip. This form of
wing, which is shown at Fig. 36 A, would offer certain structural
disadvantages, but even wdth the forms of wings generally used
to-day there would bo a marked improvement in eflBciency if
a form such as shown at Fig. 36 B were used in which the

Securing Uniform Pressure Distribution 83

vings are widest or have the greatest chord at the center and
gradually tapering away to small chord dimensions at the tips,
rhe disadvantage in wing form of either of the types A or B,
Fig. 36, is that there would necessarily be a grading down of
the total depth or camber of the section to correspond to the
lessened chord. Lanchester, in experimenting with wing plan
fonns, suggested the parabolic plan forms shown at Fig. 36 C
and experiments have demonstrated that this would yield very
good results that would be more satisfactory than those
obtamed with the rectangular shape j&rst used.

The plan form and sections of the wings of birds have been
previously considered, but it is not always possible to select
the best type of aerofoil by their wing section, neither is it
possible or desirable to approximate their wing plan in making
airplanes. The plan view given of a soaring bird, the alba-
tross which has a wing spread of high aspect ratio, would be
diflScult to dupUcate in an airplane wing on account of structural
considerations. Two forms of wings that have been patterned
with the object of securing greater efficiency than with the
r^ar rectangular^form are shown at Fig. 36. That sketched
at Z) is the wing plan of the Bleriot monoplane, while that at
-B is the German Taube wing. Some similarity between
this wing plan and that of the bird is evident, as a portion of
the wings' of the albatross near the tips has a decided ''sweep
back, " or retreat, which is also seen in the Taube wing plan.

The aspect ratio of the wings of the albatross is about 14,
meaning that the wing span is approximately 14 times the
3hord. The average airplane will have an aspect ratio ranging
'rem six to eight. The shapes of birds' wings, both as relates
o the section and the plan view, are imdoubtedly determined
)y other considerations besides those of aerodynamical effi-
iency. It is evident that the habits and mode of flying of the
>ird have a material bearing on the wing plan. It may be
aid, however, that birds which in their flying more nearly
approximate the airplane have wing plans that would no doubt
>e satisfactory on the soaring machine if constructional diffi-
!ulties did not intervene to make their practical appUcation of
omewhat dubious value.

84 The A. B. C. of Aviation

Airplane Wing Construction. — Having considered at some
length the aerodynamical properties of airplane wings and
aerofoil sections, we will now proceed to discuss the wing
structure from the practical viewpoint of the airplane con-
structor rather than that of the designer. As will be evident
from the illustrations at Fig. 37, the wing skeleton before
covering is a framework consisting of two longitudinal spars
which are joined together by equally spaced ribs running from
the leading edge to the trailing edge of the wing. The section
of the aerofoil is always greatest at the front spar because
most of the lift occurs near the leading edge. By employing
spacing strips of the proper curvatm-e it is, of course, possible
to obtain ribs of any section, and it is the degree of camb®
given the ribs that determines the lifting properties of the
wmgs when the framework has been covered.

The ribs are built up of narrow strips of wood about an
inch wide and a quarter inch thick, which are placed, at the
top and bottom of the curved central rib member that de-
termines the camber of the aerofoil. The front ends of these
strips are connected to a small moulding or leading edge spar
that is termed the ''nose" of the wing. The various ribs are
tied together by light round wooden rods that extend from
one end of the wing to the other. All portions of the wing
structure are glued and screwed together, so that while a lArgp
number of individual pieces are employed in the wing fi:ame
the methods of joining them together are so secure that the
completed structure has surprising strength for its weight.
A fabric is stretched tightly over the wing frame and is fastened
to both upper and lower surfaces of the ribs and spars.

The leading edge is sometimes given a positive curvature
by using a thin veneer of wood so as to give the cloth a definite
form at the entering edge of the wing. Wire bracing is ex-
tensively used inside of the wing to stiffen it. The tie wires
join the front and rear spars and are of great value in stiffening
the wing structm-e. The rear spar carries only a relatively
small percentage of the total load of the wing, and for that
reason is usually considerably smaller in section than the
front spar. Wing spars may be made of either ash or spruce,

fVuig Covering Fabric 85

and experiments that are being made may demonstrate that
metals such as aluminum may be used advantageously for
this purpose. The ribs are usually made of poplar or spruce,
though in some cases mahogany has been employed.

WING COVERING FABRIC

The wing covering is a fine, closely woven linen and especial
care is taken to secure both strength and lightness. The

A' wing <fifh Balancing Flap
B-Wing wifhout Bslsncing

CutOUfforBilancing ^'^P
Hap or Aeleron
Bracini^ Wires ,, ResrSpsr-"-

Jrailing Edge Tube

3-Covered Airplane Wing Viewed from Borti

Fig. 37. Typical Airplane Wing Sheleion and Appearance after It is Covered
with Fabric.

weight of airplane wing fabric generally used will varj- from
four to five ounces per square yard. Its tensile strength varies
from about 75 pounds per inch width in the warp du-ection
{i.e., those threads of a fabric that are stretched lengthwise
in the loom when the material is woven) and of about 100

The A. B. C. of Aritaion

3 per inch in the wefl direction. The weft threads are
shorter than the warp threads, as they are those that arr
carried back and forth by the shuttle in weaving. Owing tn
the greater strength of the fabric along the weft threads it is
usually attached to the wing skeleton so that the warp threads

Fig, 38, Skeleton Structure of Aileron or Balancing Flap at A (Abovt) and of
Stabilizer at B (Below).

run in the same direction as the ribs. No matter how finejj
woven the hnen is, it is apparent that it cannot be made eith^
air-tight or water-tight. It is also evident that it would be
difficult to stretch the linen covering so it would be uniformly
tight in all directions,

WHY "dope" is used FOR WINGS

ith^B
be
Daly

The fabric is made air-tight and water-proof and is also
stretched to a taut surface like a drum head by the use of
chemical preparations called "dope" in the trade. Pra(
tically all of these are cellulose acetate dissolved in soni

How Fabric Is Fastened 87

solvent such as ether, alcohol or acetone. A number of coats
of this ''dope" are given the wings and each is allowed to dry
thoroughly before the next coating is applied. Owing to the
highly volatile nature of the solvents used, this drying is fairly
rapid. The first coat penetrates all the spaces between the
threads and also penetrates the fibers of the threads them-
selves. As the drying proceeds the substance contracts and
brings the threads more closely together. From four to five
coats of " dope " are appUed to the surface of the linen, the
increase in weight due to the use of the "dope " being about one
and one-half oimces per square yard. The ''doping" is said to
increase the strength of the fabric by about 20 per cent.

HOW FABRIC IS FASTENED
■ . • •

The fabric is called upon to sustain a load of about 20
pounds per sq. ft. at a flying speed of 70 miles per hour,
so it is securely attached to the ribs. The method generally
used is to tack through Ught strips of cane or wood which acts
as a spacing member to prevent the tack heads from breaking
the linen. A certain amount of the "dope" penetrating the
linen will stick it to the ribs and in some cases a stitching of
flax cord is used to tie the fabric firmly to each wing rib at
both upper and lower surfaces. Wings that have been tested
to destruction demonstrate that this method of fastening is
extremely strong, and the writer has seen wings that have been
damaged in wrecks in which the main spar has fractured and
yet the fabric will be held securely to the ribs. When the
stitching is employed, the cord and knots on top and bottom
of ribs are covered with narrow strips of fabric about two
inches wide which is securely "doped" into place in order to
provide a smooth covering and to lessen the skin friction.
In order to give a smooth finish to the wing after doping it is
sometimes smoothed down with sandpaper and a coat of spar
varnish appUed.

Airplane Wing Bracing. — Mention has been made pre-
viously of the strength obtained by the biplane arrangement
of wings because a set of fitting surfaces are held together by
tension wires passing in three dimensions, forming the assembly

The A. B. C. of Aviation

into a very light box girder. Referring to Fig. 39 it will
be seen that wires are placed between each pair of struts or
compression members and that these are tension members
which tend to bring the wing spars tightly against the struts of
spacing members. One wire extends from the top rear spar
to the bottom front spar. The other from the top front spar

Front Spar-^^

/Rear Spar

Cord-">

Plumb
Bob

'fnferp/ane Strut
Under Compression

r Rear Spar

^^Front Spar

Fig. 39. Diagram Showing the Use of Incidence Wires between Planes Mounted

in Staggered Relation.

to the bottom rear spar. These wires are called "incidence"
wires, as they keep the planes in the proper angular relation
to each other.

One advantage of a biplane is that the wings can be com-
pletely assembled and braced up independently of the fuselage.
This means that they can be handled as a unit and readily

Airplane Wing Bracing

installed. A typical wing section assembled on one side of the
biplane fuselage is shown at Fig. 40. When the airplane is in
%ht the lift exerted on the wings will, of course, tend to
force them up while the weight of the fuselage tends to force
them down at the center. The result of this combined force
is that the wings tend to fold up from the tips inward towards
the fuselage. It will be evident that bracing wires are neces-
sary to prevent this. The upward pull of the upper parts
exerts a Uf t and puts some of the diagonal wires under a
tension loading. The lift on the lower spars imposes a com-

Cabane Struts

Center
Section^

Upper \Vmg^

,'Lancfmg
Wiro.

"^^^eiage

Overhang

Supporting
Trestle

^^. 40. Diagram Showing How Braced Biplane Wing> Assembly Forms a Com-
plete Structure That May Be Easily Assembled as a Unit to Biplane Fuselage.

pression strain in the spacing struts between the planes.
Under this condition the top spars are in compression and the
lower ones under tension. When the machine is in flight
the load is carried by only one set of wires which are, there-
fore, known as lifting wires. The opposing diagonal wires do
not carry any load when the machine is in the air, but, how-
ever, when the machine alights and the wings lose their lifting
effect the other set of wires is brought into play, and for this
reason they are called landing wires. When the machine is
in the air the flying wires are in tension or stretched while the
landing wires are slack. When the machine is resting on the
ground on its landing gear the conditions are reversed and the

The A. B. C. of Aviation

Loads on Airplane Wing Wires 91

flying wires do not cany any load while the landing wires are
in tension. When the machine is resting on the ground the
top wing spars are in tension and the bottom wing spars are
under compression. Obviously the spacing struts between
the wings remain under compression all of the time.

LOADS ON AIRPLANE WING WIRES

An airplane wing is not only subject to a lift reaction, but
also a drift reaction. As the machine flies through the air
the pressure of the air against the wings exerts a horizontal
loading that tends to fold the wings backward at the same time
that the lift reaction tends to fold them upward. Horizontal
bracmg wu-es are provided in the wings to prevent the rear
spar from bending backward and are known as drift wires,
while compression struts are placed between the front and
rear spars to hold the front spar at the correct distance. In
some auplanes special wires extend from the front end of the
fuselage to both front and rear spars of the wings to take the
drift reaction. These wires are clearly indicated in Fig. 42.

The bracing wires are called upon not only to resist the
elementary forces considered, but while performing evolutions
in the air they may be subjected to combination strains^result-
ing from loads coming in different directions that cannot be
computed accurately. It is therefore important that the
bracing wires have a wide margin of safety over the actual
requirements. It is also evident that one of the important
items in connection with airplane maintenance is to make
siire that the bracing wires are always at the correct tension
and that they are securely fastened and not frayed or weakened
in any way. In order to prevent the bracing wires from
rusting, those that are inside of the wing structure are painted
or enameled, while the bracing wires that hold the planes
together and which can be easily inspected are kept covered
with a cojating of graphite grease. In tightening bracing
wires it is important that only the proper amount of tension
be given, as, if the tumbuckles are tightened too much the
interplane struts are apt to be bowed and their strength
greatly reduced.

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. 5. C. of Amotion

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Airplane Wing Form 93

AixpUme Wing Fonn. — Mention has been made previously
of the influence of varying wing fonns if considered from their
plan view and a number of simple diagrams have been pre-

Leadinggnd Trailing.
Edges indintd but
parallel

■■■Tractor Screw

■Planes have
decided
"Sweepback '

Fig. 43. A Comparison between Two Accepted Types Showing How the Ideas
of Designers Difier. Kote That the Plane Shown at A Has Upper Wii^:s of
Greater Spread Than the Lower, While the Plane Shown at B Has Wings
<A die Same Spread.

sented showing typical wing plans. The arrangement of the
airplane supporting surfaces in relation to the rest of the
airplane structure and the manner in which theoretical forms

The A. B. C. of Aviation

Airplane Wing Form 95

ere modified to meet practical conditions may be clearly
ascertained by referring to Figs. 43 and 44. The plan at A,
Fig. 43, is a typical training biplane which has both a pro-
noimced forward stagger and an overhang as well, and the
upper and lower planes have a decided retreat or "sweep
back." The function of this is to give a certain inherent
stability imder the influence of side gusts as will be explained
later. It will be observed that the ailerons or balancing flaps
are larger at the tip of the wing and that, when in the normal
flymg position, the wing has a greater chord at the tip than
it has nearer the airplane body. The function of this swelUng
out of the ailerons is to provide more surface in order to
compensate for the les^^^^ed lifting influence due to eddy
currents which exist around the wing tips.

If one compares the plan at A with the arrangement
shown at B, Fig. 43, which outlines a very successful machine,
it will be evident that all designers do not avail themselves of
the aerodynamical advantages to be obtained by mcorporatmg
some of the finer points of design. The biplane shown at B
has both upper and lower wings of the same spread and the
leading edge of the wmg is at right angles to the fuselage.
Both upper and lower wings have the same spread and prac-
tically the same amoimt of surface and both are provided
with balancing flaps or ailerons whereas the machine shown
at A has ailerons only on the upper planes. It is evident
that it is much easier to build a machine when planes of
the same size are used, and the installation can be con-
siderably stronger when the wings have no ''sweep back"
or retreat.

If one studies the plan views shown at Fig. 44, some imusual
airplane forms may be seen. That at A is the German AGO
tractor biplane and has wings of the very peculiar form depicted
in which both leading edge and trailing edge taper from the
fuselage toward the wing tip. The angularly placed wing
spars actually meet at the wing tip and it is claimed for this
design that not only are some of the advantages of the retreating
wing plan obtained, but that a wmg plan form that more nearly
meets theoretical conditions than other form is seciu'ed.

96 The A. B. C\ of AriaHon

Mention hsL& been pre\'iously made of the advantages obtained
by ha^'ing the greatest chord of the wing near the fuselage and
having a decreasing chord toward the wing tip. In the form
jihown at B the icings have a tapering leading edge so that the
effect of a retreat is obtained to a slight extent at that point,
but there Ls a straight trailing edge which is at right angles to
the center Une of the fuselage which would seem to entirely
nullify an}' supposed advantage gained by the tapering
leading edge.

All of the machines shown and thus far discussed have been
of the tractor t5T>e with the propeller or air screw moiuited at
the front end of the fuselage. A distinctive and imconven-
tional t}T>e, which is shown at C, Fig. 44, has a pusher screw
located back of the wings, buClit the same time follows the
asual construction in which an entirelv covered-in streamline
Ixidy Ls used instead of the usual open-work or outrigger
construction which is necessary to carry the empennage in
the usual pusher type. While the wings of this machine are
set with the decided sweep back or retreat, a pronoimced stagger
Ls also provided. The ailerons, or balancing flaps, are placed
on both upper and low^er wings and are of the form that are
enlarged near the tip, instead of the usual simple type, such
as shown at B.

A study of the various designs, shown at both Figs. 43 and
44, will show that various designers have different opinions
regarding the best plan form for the empennage members.
»S^)me of the stabilizers have gracefully rounding sides, while
otlujrs are approximately triangular in form. There is also
some difference in the form of the elevator flaps, but there is
not much difference in the area provided for these surfaces
relative to those of the main aerofoils. Very little is being
(lon(3 at the present time with unconventional plane forms,
Ixicause practically all of the development work is being
conccintrated on the improvement of the power-plant. Almost
any type of airplane will fly if it is given power enough, regard-
Iciss of the shape or arrangement of the supporting and auxiliary
surfaces if standard aerodynamical principles are not departed
from too greatly.

Planes vnih Longitudinal Dihedral 97

PLANES WITH LONGITUDINAL DIHEDRAL

PracticaUy aU airplanes at the present time are provided
with stabilizing and control surfaces at the rear of the main
supporting members, but some airplanes have been built in
which the elevator has been placed at the front, but this is no
longer considered good practice. While it was satisfactory with
airplanes of early design that had relatively low speeds, the
defects of this system were made apparent as soon as the
airplane had been developed to a point where greater speeds
were obtained. There have been types of airplanes developed
that possessed no stabiUzing surface as distinct from the main
supportmg surfaces and in these the arrangement of the main
planes was in a pronounced V or the planes were given an
exaggerated retreat or sweep back, which is sometimes called
a longitudinal dihedral, which was said to assist in making such
a design automatically stable. With this form it is nece^ary
to give a decreasing angle of incidence toward the wing tips
and also to change the camber of the wing from the center
section to the tips. The function of the wing tips is then such
that they act as longitudinal stabihzers.

One of the disadvantages of this construction is that it is a
more difficult form to build than the conventional design,
which in plan has supporting surfaces in the form of a parallelo-
gram. In order to secure strength the wings must be con-
siderably heavier. Another disadvantage is that the aspect
ratio is not as large as would be the case if the leading edges
of the wings are placed at right angles to the center line of the
fuselage. Any airplane having a pronounced sweep back has
a lower aspect ratio than the usual construction would have
with the same length of leading edge, and as the efficiency of
the lift decreases with a lessened aspect ratio, the V wing
arrangement would produce less lift for a given weight of sup-
porting surface than would be the case if the wings were
arranged approximately in the form of a parallelogram as
shown at Fig. 43 B, instead of having a pronounced retreat
as outlined at Fig. 44 C. It is evident that the decreasing
camber of the wings can be obtained only by using ribs of

98 The A. B. C. of Aviation

different fortos at various portions of the wing and that this
results in added expense. The longitudinal dihedral is not
used to any extent at the present time because its theoretical
advantages do not balance the practical and structural disad-
vantages inherent with this design.

INFLUENCE OF LATERAL DIHEDRAL

While the longitudinal dihedral is not used to any great
extent the lateral dihedral has been apphed in many designs
because it aid§ in securing lateral stabiUty. A dihedral angle
is obtained by inclining the supporting surfaces up from the
center of the fuselage so that the wing tips are higher than
the other portions of the wing. A monoplane having a pro-
nounced and somewhat exaggerated lateral dihedral is shown
at the top of Fig. 45, imder normal flying conditions. Just as
is the case with the longitudinal dihedral, the effective span
or wing spread is not represented by the actual length of the
leading edge, but by projected distances A and B, which are
termed '' horizontal equivalents.'' It will be observed that
under normal flying conditions, the distance A is equal to the
distance B. This, of course, results in the lift of one wing
being equal to that of the other. If, however, a gust of wind
causes one side of the machine to tip, as is shown in the lower
part of Fig. 45, it will be apparent that the horizontal equivalent
of the lowest wing which is shown in a horizontal position and
which is represented by the letter B becomes greater than
that of the other wing as represented by the distance A.
The wing B will have a greater lift than wing A and therefore
will tend to rise while wing A will depress until the normal
flymg position is reached.

While the automatic stabilizing effect is not directly pro-
portional to the difference between the horizontal equivalents
A and B, and while other factors, such as amoimt of keel surface
and disposition of the center of gravity, affect the automatic
recovery, at the same time the lateral dihedral offers some
advantages. Experiments in the wind tunnel have shown
that moderate dihedral angles up to 14 degrees included
angle, or 7 degrees angle at each wing, do not reduce

Influence of Lateral Dihedral 99

the aerodynamical efficiency appreciably and at the same
time some degree of automatic lateral stability b secured.
A well-known training machine of the tractor biplane type has
a lateral dihedral of 4 degrees on each wing or a total included

Pig. 4$. A Honoplane Having a Somewliat Ezaggeiated Lateral Dibednd.

ai^e of 8 degrees between the two. This means that instead
of the wings being placed 180 degrees from tip to tip as would
be the case if they were absolutely horizontal, the space between
wing tips would be 180 plus 8 degrees if measiu^ from un-
demeath and 180 minus 8 degrees if measured from the top.

»'.i^iO,>

100 The A. B. C. of Aviation

AIRPLANE WING BRACING

If considered purely from an aerodynamic point of view the
monoplane has decided advantages and is a more efficient form
than the biplane, but as has been outlined in a previous discus-
sion of this subject the reduced efficiency of the biplane is
more than compensated for by the increased strength of the
biplane structure. The advantages of the biplane are so
firmly estabUshed at the present time that this type of machine
is almost universally used. The first biplane forms were poorly
designed and had so much exposed wiring and struts of such
clumsy form that it offered considerably more resistance than
the smaller and lighter monoplane did. The latter offered less
resistance because it had no struts and was enabled to operate
with higher efficiency because there was no interference be-
tween upper and lower surfaces as is the case with the biplane.
Improved design and careful bracing have made it possible
to build biplanes that are very fast and that are able to Uft
heavier loads than a monoplane of the same effective area.

As the size of machines increases the biplane structure of-
fers greater advantages. We have seen that the construction
of a wing consisted of two wing spars which were joined together
by transverse ribs. The connection of the wings to the
fuselage of the airplane is at the inner end of the wing spars so
that we can consider one side of any airplane as a cantilever
beam. The two methods of bracing the monoplane are shown
at Fig. 46 A and B. The flying wires, which are those that
assist the wing in carrying the load by transmitting some of
it to the fuselage, are indicated by soUd black Unes while the
landing wires are indicated by dotted or broken lines. '• The
scheme shown at A is the most common one as the construction
outUned at B has been practically abandoned. The biplane
structures which are shown at Fig. 46 C and D may practically
be considered true girders of the box or trellis type. As is
true in the preceding example, the flying wires are indicated
with solid black lines, while the landing wires are shown by
broken lines. By these comparisons it can be seen that the
biplane system may be so worked out as to offer a stronger
'""d more rigid construction than is possible with a monoplane

'em, weights and supporting surfaces being equal.

Airplane Wing Bracing

101

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(^^wvvvvv

AVVVVVV'ol

kvvvv

Side Bracing of Airplane Wings 103

Buid while it is also adaptable to the usual biplane form as
sAown at E, its field of greatest utility lies in the imequal chord
fcriplane having a pronoimced forward stagger. In the early
days, Breguet designed a single lift truss biplane of the form
shown at Fig. 47 (?• As his main object was to vary the angle
of incidence of the wings automatically, these were hinged to
tubular spars and a spring bracing member having some de-
gree of flexibiUty extended from the tubular spar to the rear
spar of the wing. This construction brought the spars con-
siderably nearer together than they would be in the conven-
tional design wing and the entire structure was not as strong
as the other designs employing double lift truss construction.
The /-type side bracing that has been used in an effort to
reduce parasitic resistance is shown at Fig. 47H. In this
construction special sockets are used which havb long bases
reaching from the front to the rear spar, and these project
from the wing surface an appreciable distance in order that
the single strut will project into the socket far enough to secure
the necessary strength and rigidity. The Martin X-type
ade bracing, which is shown at Fig. 47 /, has many advantages,
uid while it offers but little more resistance than the /-type
;hown at H, it eliminates the bending moments due to the
cantilever socket construction. A modified system of the
'T-type side bracing is shown at Fig. 47 J. This is a single Hf t
russ designed by Curtiss and built up of two steel tubes, one
>f them being bent in such a form that it can be readily fastened
o the front strut for an appreciable length. When either of
heii:-type side bracings are used it is possible to streamlme
hem so effectively as to secure a marked reduction in resistance.
[Tie X-type side bracing, which is shown at Fig. 47 K and L, is
lot used to any extent at the present time, though it would
eem to offer some advantages over the conventional construc-
ion shown at A and B, because it eliminates the bracing wires.

AIRPLANE BRACING WIRES

Two kmds of steel wire are used for bracmg, one being a
ard wire, while the other is a flexible cable or steel rope,
lie stay wire loops and the method of forming eyes in both

The A. B. C. of Aviation

fyfxihUi cables and hard wire by the use of thimbles, around
liirkh iiui flexible cable is bent and afterwards securely held
i/^^y^r by a serving of soft steel or copper wire well soldered,
U ^ti^mu at Fig. 48. The hard wire loops are made by using
ovfil i*Af\\H of wire as sleeves and bending up one end of the wire
H^ ^tiown, afterwards soldering the whole to insure that the
imr\.^ will Htay in the proper relation. In order to insure
iUiii tho l)racing and stay wires will be properly tightened^ tum-

r ■•■»

Wire

'""H%h Silt"""
flilitf-yf$n Turnkvck/9 Zji'

>/o/# $199 4 ^. Hot* SizeB

u^-^— .^o-.'-.' So/c/eree/unekr

Shellackeel
Harness Thrtad

* '

f/f<li/»fM

*i»r i4h 1^1*

/OCofb \r/OCoits
-090y¥ir9 DVWin

*Wk^ JIA'Wi^ JOiytftn MO'Wire

HofSinB

S/ot

* ^Thickness

Jhk^^u^cn Tt/mbvcicMJ*

Fitf. 48. Details of Standardiied Thimbles and Tornlmckles.

hiiiklos an^ interposed in each wire. These may easily be
tight imuhI by inserting a pin in the tunibuckle body and, after
tlie ial)los have Invn tight on(\l to the proper degree, the tum-
burklos i\Ti> **safoty wiroii*' by passing copper or soft iron wire
iluough tho turnbuoklo Ixxly and then wrapping it through
auil «rc>uud tho ovos in such a way that the tiunbuckle body
lanuiii Ihvoiui* IooscmuhI without the safety wire being cut and
ivnu»\c'il. 'V\\\> r«MuliM>i it itui>i>ssiblo for a cable to become
huk^e tliu* ti> \ihr!iti»»ii whilo tho machine is in .flight. The
itppc'iulc'd ilatit ic^gMiiliiii^ tht^ various cables and hard wire, as
Well iu-- ilu' ltlllllMll'Klc'^^ i^tMUMally \isi\l in airplane wire bracing

Airplane Bracing Wires

105

-work, has been suggested by the Aeronautic Division of S, A. E.
This gives sizes and strength of wires of various kinds.

Hard Wire Loop. — ^This consists of an oval coil of wire

through which the hard wire is sUpped, bent in the form of a

loop, again inserted, and the end bent over against the coil.

- The whole is then soldered. This is identical with the present

British standard.

Flexible Cable Ends. — The sketch shows the cable end
"wrapped around a ''standard thimble.'' The length of splice
from pointed end of opening in thimble was represented by
. "splice plus or minus 3^ inch." The end of the spUce is
wrapped with a serving of shellacked harness thread. Dimen-
aon A represents the distance from end of opening in thimble
to end of serving.

Diameter
of Cable

Length of
. Splice

Number of
Tucks

Length of
Serving

Full Strength
of Cable

V«7xl4....

K 800

Vs 7x19

3 over

H 2000

V32 7xl9....

W4.

core buried

}4 2800

Vie 7x19

iVs

4 under

IVa.

H 4200

Vk 7x 19

lii

M 5600

Galvanized Non-Flexible Ends. — The cable end is wrapped
about a thimble, with a total length of spUce indicated by L;
0.041 inch soft steel wire is to be used for wrapping, and the
sketch indicates two spaces left between convolutions of the
wrappmg wire, width of the spaces being indicated in the
table. The accompanying table gives the sizes and strengths:

Diameter of Cable

Vl« 1 X 19
% 1 X 19
Vs 1 X 19
V32 1 X 19
Vie 1 X 19
/32 1 X 19
74 1 X 19

VA
2

2J^
2M
3

Space

Vs
Vs

V
V

Wind

Full
Strength
of Cable

500
1100
2100
3200
4600
6100
8000

106

The A. B. C. of Aviation

Thimbles. — ^These thimbles are shown by appropriate
drawings. The sizes are indicated roughly by the following
table :

Size of Rope

'A .

16- .
'32. .

U..

16- •

8 • •

V.
'A

'A
V.

Thickness
of Thimble

0.075

0.12

0.17

0.21

0.24

0.27

0.30

0.33

0.39

Width
of Eye

0.35
0.35
0.40
0.50
0.60
0.70
0.80
0.90
1.00

Length
of Eye

0.70
0.70
0.80
1.00
1.20
1.40
1.60
1.80
2.00

Ttimbuckles. — Detail dimensions of both short and long
types are given in Fig. 48. The following main dimensions
are recommended for immediate adoption:

(With either two eye ends or one eye and one yoke end.)

Length of barrel

Length between eyes:
With threads flush with ends of barrel

With maximum extended

With minimum extended

Short

4Vl6

3V4

hoot

8»/i.
5V»

Strength (Lbs.) S. A. E. Numbers

Short

500
1000
1500
2000
2500
3000
3500

Long

500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
6,000
7,000
8,000
9,000
10,000

Typical Wire Bracing Arrangements

107

TYPICAL WIRE BRACING ARRANGEMENTS

The arrangement of bracing wires on a number of airplanes
different design is given at Fig. 49, so that the student may
itermme the various kmds of bracing ordinarily used. The
mplest construction is shown at A. In this, the overhang

^-Overhang noi braced by wires

- ' ■ ■ ■ I —I — ■ — ^ X

landing Wires for Overhang,

i i iili if '^^^'^^

ir I I I I I

I I I

! y J 1

-Two Wheel Landing
Gears

flying

Wires for ^

Overhang*'

Wing Skid"-

Flying^'
Wires

,'Cabane
Struts

-Wing Skid
— Two Wheel Landing Gear

inclined
Struts-

Sfraight y
Strut"'

Inclined Strut under''
tension Flying under
Compression when landing

Inclined

Strut

Brace

'^'Strort Span
Lower Plane

^^^Double Pontoon landing
Gear of Seaplane

g. 49. Showing Arrangement of Bracing Wires on a Number of Airplanes of

Different Design.

■ the top plane is not braced by any wires and all of the strain
^oduced by the hft while flying or the reverse load when
nding must be taken entirely by the wing spars. In the
actor biplane, shown at B, the overhang is braced by flying
ires which extend from the bottom of the outside strut to
te wing spars. The overhang is also braced by landing wires

108 The A. B. C. of Amotion

which are stretched over cabane struts on the top of the up
plane. In tHe tractor biplane, shown at C, the struts are inclii
instead of being straight up and down as in the form shown
A and B. The difference in landing gear construction a
bracing can also be easily determined from these illustratio]
Two-wheel landing gears of silnple form are used on the plar
shown at A and B, while a three-wheel landing gear of son
what stronger construction that also offers more resistao
is shown at C. The seaplane shown at D, Fig. 49, has t
overhang braced by an inclined strut which is under tena
while flying and under compression when landmg, T
arrangement of the drift wires which extend from the front
the fuselage to the wings is also apparent. It will be obs^v
that the wings of the seaplane are set at a slight dihedi
angle and that the pontoon landing gear must offer considerab
more resistance than the simpler wheeled landing gears of t
land machines.

CHAPTER VI

AIRPLANE FUSELAGE CONSTRUCTION

Wright Starting System — ^Design of Fuselage Framework— Airplane
Oesign Considerations — Reduction of Parasitic Resistance — ^Airplane Fuse-
age Forms — Complete Inclosure Important — How Coincidence of Centers
s Obtained — ^Landing Gear Forms — ^Wheel Tread Depends on Spread —
^oods for Airplane Parts — Metals Used in Airplanes — ^Table 8 — Table 9 —
Table 10.

When airplanes were first designed the type of construction
)wed was to use the wing structure as a main framework
ch carried the aviator, the power-plant and the propulsive
iws while control and stabiUzing surfaces were c^-rried by-
riggers and in a number of the early biplane designs the
trolling surfaces were placed at both front and rear of the
g structure. In the construction that was first followed in

Bleriot monoplane, the power-plant was carried at the
it of the machine and was mounted in a framework or body
ch served to carry most of the weight, inasmuch as the
b for fuel and the seat for the pilot were included in the
ilage. With the tractor monoplane type of construction
control surfaces were carried at the back end of the machine

no control members were placed at the front end. The
antages of this construction were so marked that the older
a was discontinued and practically all machines, whether
he single plane or multiplane type, were designed on the
y monoplane principle of having the wing sections attached
. fuselage which carried most of the weight and the control
aces instead of the type that offered the most resistance
^hich practically all of the weight was carried directly %y
wing structure.

Two early biplanes are shown at Fig. 60. That at the top
he historic Wright creation with which the possibiUties
aechanical flight were first demonstrated to^an unbelieving
ntific world. The type shown below it is a Curtiss creation
t did some wonderful work for the early days" and which

103

The A. B. C. of Aviation

proved to be not only a very reliable type, but one in which the
qualities of safety were best developed. It will be observed
that there was considerable difference in the design of these
two pioneer forms. The Wright machine had its power-pIaDt
carried on the lower plane, and at one side of the seat occupied
by the pilot, which was also on the lower supporting surface;
The drive was by chains to two large diameter, relatively slow,

Fig. 50. Two Early Biidanea, That at fkt Top being the ffistoric Vrlcht UacUnt
Which Demonstrated the Poasibilitiea of Mechanical Fli^t. The Lower
One is on Eoily CurtisB Machine of Remarkably Dependable Chantcteriatic*.

speed pusher screws. In the Curtiss machine the power-plant
was placed back of the aviator and mounted approximately in
the center of the gap so that the propeller thrust came about
half-way between the upper and lower wing surfaces. In this
machine the power transmission system was very much simpli-
fied by baving the propeller directly connected to the engine
crankshaft and revolving it at engine speed.

Another marked difference was in the method of securing
lateral stability, as in the Wright machine the wing tips were
made flexible, and it was possible to warp them so that the wing

Early Wright Starting System 111

iiirvature at the tip and for a certain distance toward the

center was changed so that on the high wing one had a decreased

Jurvature and a lessened Uft, while on the low wing one had a

more pronounced camber and a correspondingly increased

Ufting effect. In the Curtiss biplane lateral stabiUty is secured

by means of small auxiliary wings or ailerons attached to one

of the wing spars and so connected to a shoulder yoke that

the pilot could incline his body toward the high side of the

machine and by so doing regulate the position of the aileron

on the high side so as to give a depressing action, while that on

the low side was tilted so that a Uft on the under surface would

give a greater lifting effort and consequently tend to right the

machine. In both of the early biplanes shown, the elevator

was in the form of a small biplane structure and was carried by

outriggers at the front end of the machine. The vertical

nidders by which the machines were steered from side to side

^ere carried at the back in both types.

The most marked difference in which the two pioneer types
of airplanes differed and which tad a material bearing on the
design was in the matter of starting. The early Wright
^^chines used a system of launching the airplane which per-
^tted it to rise in a preUminary run of a little less than 75
^eet, but it involved a rather elaborate launching mechanism,
^d if the airplane landed at a point remote from the launching
gear it could not ascend again. The foreign designers and
Curtiss m this country beUeved that the wheel type landing
gear would be the most practical even if it did involve a run of
several hundred yards over the ground before sufficient flying
speed was obtained to enable the airplane to rise in the air.
The system originated by the Wrights is not used at the
present tune m connection with land machines, but is utilized
in a modified and unproved form for launching seaplanes from
the decks of ships. Even the Wright Brothers soon changed
their construction to a combined wheel and skid landing gear.

EARLY WRIGHT STARTING SYSTEM

The form of starting apparatus adopted by the Wrights
>n their first creation depended upon the rapid acceleration

112 The A. B. C. of Amotion

given by a falling weight. The airplane was mounted on a
small wheeled truck which ran on a track. A rope was at-
tached to the truck and ran through sheaves and over a
pulley, supported on a high tripod, and a heavy weight was
attached to the rope, so that when it was released and fell, it
would draw the small truck along the track and the airplane
would be travelling at sufficiently high velocity by the time it
reached the end of the track, so that the revolving air screws
were delivering enough thrust to lift the machine into the air.
With this construction it is possible to use skids for an alighting
gear which form part of the framework of the airplane. An-
other thing made possible by this method of launching was
the fact that a smaller amount of surface and a reduced
engine power was necessary to secm^e flight. This type of
construction was not encoiu^aged because with wheels one is
independent of starting platforms, rails, or catapult launching
devices, and for this reason the wheel landing gear became
universally applied and is now used on all land machines.

One of the advantages brought up for the skids was that
they acted as a brake^ and retarded the airplane movement
after it touched the ground, whereas the wheel form did not
enable the aviator to make a quick landing. This resulted in
a number of landing gear designs in which wheels and skids
were combined, though these gears weighed more than the
types in which wheels alone were used. In the early Curtiss
machines the motion was arrested by a simple spoon brake
actuated by the foot and working on the tire of the front wheel,
this serving to arrest motion over the groimd soon after the
plane alighted. In the early Cmiiss machines no shock
absorbing means other than that provided by the resiliency of
the tires was incorporated in the construction. In the first
Bleriot monoplanes, which were so efficient a flying machine
that their construction is followed in many respects in the
later types of planes, the two-wheel alighting geSjr was provided
with shock absorbing means in the form of coil springs on the
early machines, which construction was afterward modified to
use shock absorbers of rubber. A discussion of some of the
modern type of alighting gears to follow will show how these

Design of Fuselage Framework 113

pars have been simplified, strengthened and improved in
.ction.

DESIGN OF FUSELAGE FRAMEWORK

One of the disadvantages of either of the machines shown
.t Fig. 50, in which the power-plant was placed either at the
ide or in back of the aviator, was that in event of a rough
anding, which was much more common in the early days
han it is at the present time, the aviators were very often
atally injured by having the power-plant fall on top of them

ig. 51. Captain Tictor W. PagI, Ariation Section, S. B. C, IT. S., Seated in
Rear Cockpit of Modem Tractor Biplane Showing Degree of Protection
Offered and Space Available for Pilot

Q nearly every smash. It was soon discovered that the
ystem of construction employed on the Bleriot monoplane
lad the mark^ advantage of making a machine "nose heavy"
ad that in most rough landings the position of the power-
)lant was such that it fell clear of the aviator in event of a
mash and that a considerable degree of protection was afforded
ly the landing gear and supporting framework.

Hi Th^ A, B. C. of Anation

One of rhe moRt Lmportajit parts of the modem aiiplaa
irt r.hft framework ^upportiiig the sastaining surfr ~
^mployftfi r.o carry the zreater part of the w«^t, such as
p^>wftr-plant and the useful load. The problem of building
fuHelai?ft or frame ?»ufficiently light for use in airplanes wl
f*\'f^rv ounce mii5it be accounted for. while at the same time
would fKiftfteftft the strength and endurance eseential for
work waft not difficult of solution because light and sti
matmalft were available that were particularhr well ada]
to air|:>lane framework construction.

The form of the machine has a material bearing upon
general Iine» of coastruction as will be evident by examinal
of th^; airplane types ?ihown at Fig. 50, when compared to
^h^>wn at Fig. 54. In the modem construction the
i.H t.hf; main member from which the surfaces extend, and in
ffUffU^m monoplane the fuselage may be compared to the b
(}f a bird and the aerofoils to the wings. It was soon learned,]
as a n^ult of the wind tunnel experiments, that air resistance
wan materially less when the closed-in fuselage frame was
UHf'A iriHt^^a^l of the open framework and outriggers provided
in the early forms of biplanes. A reduction in air resistance
rnmJe great;f!r speed possible with the same power and reduced
the HijpiKirljng surface necessary to seciuie sustentation.

AIRPLANE DESIGN CONSmERATIONS ^

In df.'signing any form of airplane or component thereof
iho (h^Higner must have certain basic principles in mind
Thcwr, wnni siatod in the writer's first treatise on aerial navi-
Kut'i(»n publishc^d about ten years ago, and are still applicable
io i\w (ic^Hign of modem forms. The following are principles
whic^h Hhould bo obsorvod in designing or building airplanes:

1. An airplane must have sufficient combined speed, power
find plane aroa to raise a useful load in addition to its oWn
wcMghl. The groaicr the amount of useful load lifted for a
given engine i)<>wor the greater the efficiency of the airplane.

2. Th(» greater the speed of flight the less the plane surface
r(H|\iinMl and the smaller the necessary angle of incidence of
that, plane for carrying the load.

Airplane Design Considerations 115

3. To counteract the resistance set up by the means of gain-
momentum while on the ground, which is additional to the
stance the machine will have when once it is clear of the

>\md : (a) extra power is required or (b) extra plane surface
meet the power available or (c) a better lifting effect for the
le area and power we have available or (d) an outside
jncy that will assist in launching the plane. Though extra
nwer means more weight and extra supporting area means
pore resistance, the modem airplanes nearly always have a
fcrge reserve of power, as it has not been possible to make
Jiany improvements in the present method of construction.

4. The supporting planes must always have sufficient area
O permit a low and therefore a safe landing speed.

5. The shape, camber and angle of incidence to be employed
epend upon the type of machine to be constructed and the
ieans employed for obtaining lateral and longitudinal balance
nd stability. We have seen that a plane suitable for carrying
eavy loads is not the form best adapted for high-speed work.

6. All parts of the machine should be constructed of as
trong material as possible, and the design should be such
hat the part should create as Uttle useless or parasitic re-
istance as possible. The general arrangement should be
imple and the control should be easy of manipulation.

7. The machine should be so designed that it will be
nherently stable to some degree; it should have an ample
oargin of safety and as large a gUding angle as possible.

Reduction of Parasitic Resistance. — One of the important
. .ints in which the modern airplane has been improved has
)een in the eUmination of parasitic resistance. This has been
iccompUshed by a careful study of air resistance on bodies of
irarious forms made in the wind tunnel. While the action of
air around a streamUne body has been previously shown, it
naay be well to review the definition of this form of body.
As shown at Fig. 52 A, a streamUne body may be defined as
one which when moving through a fluid or when a fluid is
inoving past it that does not cause a breaking up of the air
stream nor produce any disturbance or eddy cmrents in its
wake. It should be of such a form that the streamUnes or

116

TJie A. B. C. of Aviation

Pure Streamline Shape

Showinq how Fish approxima+es. Streamline Form /^ ^\

Sec+ion A-B

Motor
Housingy^ A

.Cock'Pif

Single Seated Fuselage with
Enclosed Motor, Monocoque Type

B D

Two Seated Fuselage with Enclosed Motor

Section A-B

Fig. 52. Illustrating the Development of the Modem Fuselage from Studies

Made of the Streamline Shape of the Fish* i

Airplane Fitselage Forms 117

air currents would be deflected in a gradual manner and which
would merge in parallel streams at the rear of the body with
practically no loss of energy.

Tests that have been made with bodies of various forms in
water which, of course, offers considerably more resistance
to the movement of a body through it than the air does, have
demonstrated that nature has worked out very efficient stream-
line shapes which were found incorporated in the various species
of fish. If one will refer to the illustrations at Fig. 52 B,
which show the side and bottom views of a very fast-swim-
ming fish, the trout, it will be observed that it follows very
closely an ideal streamUne shape as shown at A, An im-
portant consideration m the design of streamUne form is in
the fineness ratio. This is the ratio the total length bears to
the greatest width. In the trout the length is from six to
eight times the greatest width. Streamline bodies for use
in air can be less fine than those intended to be forced through
the water and at equal velocity.

Naturally, airplane designers plan the airplane fuselage
with a view to approximating as nearly as possible an ideal
streamline body which, however, had to be modified owing
to structiu'al considerations. The ideal shape for an airplane
fuselage is that of a streamline body that has sufficient capacity
to accommodate the engine, fuel tanks, aviators and the neces-
sary accessories without being excessively wide. The fineness
ratio of airplane fuselages of present-day types is about seven
to one in the average example. This means that the fuselage
is about seven times as long as its width at the widest part.

Airplane Fuselage Forms. — The airplane fuselage is made
in^two forms. In that shown at Fig. 52 C we have what is
called the "monocoque" type and which has less resistance than
any other form, and is therefore used on fast machines. In
this the fuselage is approximately round in cross-section,
its shape depending on the type of power-plant employed and
the disposition of the power-plant with auxiliary parts. Ex-
periments have shown that at 60 miles an hour a true stream-
line body measuring 3 ft. m diameter by 17 ft. in length
would have a resistance estimated at about 7 pounds. The

118 The A. B. C. of Aviation

usual airplane body resistance varies from 30 to 60 pounds
at the same speed, and this is due to the structural require-
ments in the modem airplane which called for radiators
in an exposed position, wind deflectors and a departure from
the true streamline form on account of having to carry a
pilot and a passenger. The fiiselage at Fig. 52 D shows the
form of fuselage provided on practically all two-place machines.
A fuselage of the single-seated "monocoque" type having a
revolving motor in a rounded housing might have a resistance
of about 30 poimds. That of a two-place fuselage such as
shown at Fig. 52 D might run up to 60 pounds. The greater
resistance makes the form of fuselage shown at D, a type that
is adapted to moderate speed machines, while the monocoque
body construction shown at C, due to its offering about half
the resistance, is £he type used on high-speed, single-seat
■ battling planes.

Complete Enclosure Important. — In the early days it was
not thought necessary to enclose anything -but the front part
of the fuselage, as it was believed that the resistance of the open
framework at the back would be neghgible. Experiments

Fig. 54. Showing a Typical Fuselage Without tbe Covering and Uustratiiig
the Methods Employed to Get Great Mechanical Strength with a Minimuia
of Weight.

soon demonstrated that there was a marked reduction in the
resistance if the framework of the fuselage was entirely covered
in with Unen instead of only half covered. Typical fuselage
forms with the covering removed are shown at Fig. 53 and
Fig. 54. It will be observed that the fuselage consists essen-
tially of four longerotis or longitudinal frame members of ash

^ jffoii; Coincidence of Centers is Obtained 119

which are held apart by fuselage uprights of ash or spruce and
kept separated by compression members of correspondmg
form. These wooden spacing and bracing members are at-
tached to metal fittings and the entire structure is braced by
cross wires. At the front end of the fuselage, where the
greatest load is carried^ the bracing is with flexible cable, while
at the back end, where the section of the fuselage is smaller
and where the load carried is less, single-strand or piano-wire
braces are all that is necessary. The front end of the fuselage
terminates in a steel stamping or spider which not only serves
to tie all of the longitudinal frame members together, but
which serves also as a radiator support and an anchorage for
the front end of the engine bed timbers. In the fuselage, the
uprights at that point in the frame where the greatest stress
comes are of substantial proportions.

HOW COINCIDENCE OF CENTERS IS OBTAINED

•

An important point in the de&ign of the airplane fuselage
is the proper distribution of weighty- parts and location of
supporting surfaces to secure a proper coincidence of the
important centers of gravity and pressure. The subject
is covered in a very able manner by B. Russell Shaw, writing
in Aviation and Aeronautical Engineering, who calls attention
to some pomts in au-plane design worthy of mention.

A procedure often poorly followed iri designing an airplane
s the correct balancing of the component parts and giving
hem the correct relation with the center of pressure.

Some designers draw the complete machine, locate the
enter of pressure and center of gravity, then give them the
orrect relation by shifting such weights as the pilot and pas-
mger or the gasoline tank. This method is very poor, inas-
luch as it does not allow the body struts and ties to be attached
t the proper places. The gasoline tank should be given as
3arly neutral position as possible, and not shifted.

The seats should not be moved, for once a proper and com-
►rtable arrangement is reached that arrangement should
(main, as any moving from this point may cause cramping in
a unnatural position. The body should be laid out complete,

120 The A. B. C. of Amation

taking into consideration the range of vision of the pilot. If
he is to be placed in front, as in some European machines, then
the gunner in the rear seat must have ample room for action.
It is sometimes an advantage to have two seats, one above the
other, so that the top one may be folded up allowing him to sit
almost on the floor of the body for observation, camera work
or bomb dropping through a door in the floor.

The center of gravity of the entire body assembly is found
by a very simple method shown in Fig. 55. The weights of the
component parts are multipUed by their respective distances.

AAi + BBi + CCi + DDi + EEi + FFi + GGi, etc., = ^

The first distance A is anything desired. W= the total
weight of all component parts in the body assembly.

After this is done the wings should be considered. They
should be drawn upon a separate sheet and the resulting C.P.
and C.G. determined, allowance being made for the extra
efficiency of the upper plane affecting the combined location
of the C.P.

The wings are then placed on the body and shifted until
the desired relations of C.P. and C.G. are obtained. This
will apply to a neutral tail setting. If a positive or negative
tail is used, the forces actuated by it must be taken into
account. The resulting forces caused by the leverage between
the C.P. or Ky and the C.G. or W, as well as those between
the Unes of thrust and resistance, must be gone into very
carefully when setting the tail plane so that the proper degree
of longitudinal stability may be obtained.

LANDING GEAR FORMS

One of the important problems in connection with airplane
design is in the selection of the best type of landing gear.
As will be seen by reference to Fig. 56, the important con-
sideration is to provide sufficient ground clearance so that there
will be no danger of hitting the ground with a propeller when
making a tail high landing. The tread or track must be
sufficient so that the machine will be stable when running
on the ground. At the same time the tread shouM not be so

Landing Gear Forms

^ 55. Diagrams Showing Simple Method of Weight-DiGtribudon in

122 The A. B. C. of Aviati&n

great that the machine will be txUned aroiind by one wheej
striking a soft spot or an obstruction in the groxmd when
binding. The point of contact of the wheels with the grotind
must be so arranged in respect to the center of gravity of the
machine that there will be no tendency for the machine to
nose over when making a moderately tail hi^ landing.

As will be seen at Fig. 56, a line drawn from the center of
gravity to the ground when the machine is in its nonnal
flying position should come well back of the point of contact of
the landing gear wheels and the groimd. This will result in
the machine coming to rest with the tail skid on the ground

instead of with the tail up in the air and the machine on its
nose as will result from carrying the center of gravity or
moving the axle so that the Une W would coincide with the
axle or touch the ground at a point ahead of where the wheel
tires rest on the ground. With the ordinary form of rubber
shock absorber an axle movement of four to six inches is pro-
vided, and this means that under nonnal conditions when the
machine is standing on the ground and the shock absorbers
are not extended, the distance should be at least one foot,
which will give a clearance of about half that if the shock
absorber rubbers are stretched to the limit.

Wheel Tread Depends on Spread. — The ordinary tread or
distance between the wheels depends on the size of the machine

Landing Gear Forms 123

and the wing spread. Naturally, the greater the spread the
wider apart the wheels must be. On machines having a spread
in excess of 50 ft. it sometimes is the practice to provide two
independent landing gears which may be spaced as much as
12 ft. apart. Sometimes the landing gear is a skid form
having the skids separated by 10 or 12 ft. and having a short
axle carrying two wheels which are 16 to 18 in. apart
straddling the skid. Distance members are provided so that
the wheels will track properly and the usual form of shock
absorber cable is wound around the axle and the skid. The
tread of the average tractor biplane ranging from 40 to 50 ft.
spread will be about 6 ft. An empirical figure based on
average practice would give a wheel track of about one-
eighth the effective wing span.

Another factor that regulates the height of the landing
gear besides that of propeller clearance is the maximum angle
of incidence it is desired to attain or have the wings inclined
at when the tail skid is resting on the ground. In order to
obtain a short run after the machine lands, it is common
practice to make a tail low landing and have the wings at an
angle of incidence of 15 or 16 degrees. This, of course, would
call for a very short tail skid if the landing gear was of moderate
height or a higher landing gear if a really efficient tail skid was
desired.

A nxunber of types of modern landing gears are shown at
Fig. 57. That at A is a conventional two wheel form, while
at -B a combined skid and wheel landing gear is shown. To
prevent nosing over, on some training machines a thre^ wheel
aUghting gear is sometimes provided, as shown at Fig. 57 C.
The disadvantage of the three wheel landing gear is that it
is a more complicated form than the two wheel gear which is
so clearly shown at Fig. 53, and also that it offers more re-
sistance when the machine is in flight. The machine shown at
Fig. 57 D is an unconventional machine of the pusher screw
type which has four wheels, as indicated. The disadvantage of
the three and four wheel types is that the front wheels some-
times take the full force of the landing, and as they are not as
large or braced as securely as the main wheels the landing

124 The A. B. C. of Amotion

Various Designs Employed

% SS. Showing Wheel, Axle, and ^ock Absorber Parts of Landing Gear
Suitable for Medium Weight Airplane.

Fig. 59. Landing Gear Parts for Heavy Uechin^.

126 The A. B. C. of Aviation

gear may be damaged under landi ng conditions that would no "^
materially a£Fect a two wheel landing gear.

Airplanes designed to rise from and alight on the water^
have supporting gears adapted for that medium. The simplest>
form is the pontoon type which is shown at Fig. 62 A. Thes^
form shown at B employs a main float of the angle step hydro-
plane form. The type outlined at Fig. 62 C is known as a

flying boat because the supporting wings and control surfaces
are attached to what may be considered a regular boat hull.

Woods for Airplane Parts. — Woods used in aeronautical
construction work may be divided into two classes, hard
woods and soft woods, although in reahty many excellent
woods are of medium hardness. For the same bulk hard
wood is far stronger than most soft woods, besides being more
springy and flexible as a rule. For a given weight, however,
some of the soft woods are far stronger than the hard woods,
while a notable exception to the elastic superiority of hard
woods is spruce, which is one of the most flexible and elastic
of American woods and that most generally used in modem

Landing Gear Forms

Rudder Post -4^^

1^ -^

Fuselage

TailSkla ^s''-»H^

^^^ShocMAbtorba^

Swivel ■I'^C^

"""^ ^a

^^^^^•Woad
"Hipge

Tail Skid

^^^^^^^^-Shae of Hard Steel

Fuselage:

Sk d Suppc

rl-ngF-H-n^

fS^

J""''

.(ll/l

^Rudder Post M

»l

mgs ■-.jflp^^^gj^^j,^^

•"^

(^^^^ 'Ash

7i.,7 £A;y

'■■ Ste^l Shoe ■

. -^.ffWU

ng. 6i. Drawings of Ty^cal Alrpbme Toil Skids, an Important Part of ttie
uUngGear.

128 The A. li. C. of Ariation

aircraft. Among the desirable .Ajnerican hardwoods may !>e

mentioned :

A-ppk: A fine timber and with great resistance to splittiDg.

Difficult to secure in large, clear pieces. Excellent for

propellers.
Ash: Good while ash is almost equal to hickory for strength

and is exceedingly elastic but not very stiff. Apt to split

Wfiods for Airplane Parts 129

up if of uneven grain and does not withstand exposure to
weather without becoming rough.

3lack Ash: Splits easily, is flexible and tough. Used ex-
tensively for barrel-hoops, oars and paddles.

ieech: A close-grained, hard, heavy wood; very stiff and
rather brittle, but difficult to split.

iirch: Red, white and black birch are all handsome, durable
woods of hard, close grain. Very difficult to split and
very strong. Rather heavy and cross-grained but excel-
lent for small parts where weight does not count for much.

iuttonball: *(See Sycamore).

'herry: Fine-grained, strong and free from faults, but not
very elastic. Excellent for propeller construction.

Chestnut: Coarse-grained, r.ather soft and splits easily. Strong
and durable, but will not withstand exposure to water as
well as oak.

hgwood: A hard, clear, close-grained tough wood; excellent
for propellers.

'llm: Very tough, fibrous, free from splitting and difficult
to work. Warps and twists badly under strain unless well
braced or boxed in a covering of some other wood. One of
the lightest of hard woods.

him: Nearly a soft wood, but so tough, fibrous and hard to
split that it may be included among the hard woods. Used
extensively for wooden plates, tubs, butter-dishes, firkins
and drums. Should be excellent for hydroairplane floats
or wherever toughness and flexibility are desired.

Uckory: One of the strongest and toughest of hard woods,
particularly second-growth timber and ''white'' hickory.
Easily steamed and bent; takes a splendid finish and is
excellent for skids, runners, wheels, propellers, etc. Decays
rapidly when exposed to weather.

Tombeam or Ironwood: A very hard, fine-grained durable
wood, difficult to obtain in large pieces. One of the
strongest and hardest of American woods.

laple: Lighter than most hard woods, does not split readily
except close to the end and is flexible but brittle. Stands
exposure well and will take a knife edge.

130 The A. B. C. of AviaJbim

Oak: A valuable, hard, durable, tough, strong timber, but too

heavy for most airplane purposes.
Pear: Similar to apple but more flexible. Use mainly for T-

squares, etc.
Sassafras: Very strong, fine-grained, hard and takes a beautiful

finish. Durable when exposed; will take a fine edge and

should be a very useful material for propeller blades.
Tupelo (Peppridge): A very durable, close-grained, tough

wood, free from splitting and far less known or used than

it deserves.
Walnut: Rather brittle, but strong and Ught and mainly used

in propeller construction.

Among the more noteworthy American soft woods are:

Pine (White) : Very Ught and strong, but not very flexible and
less desirable than spruce. Yellow pine is heavy, strong,
but usually very pitchy. California and Oregon pines are
flexible, tough, light and very similar to spruce.

Basswood or Bastwood: A very light, soft, strong, flexible
and tough wood of fibrous grain. Used a great deal in boats
and canoes and an excellent wood where Ughtness and
abihty to bend in any shape with freedom from spUtting or
breaking is desirable.

Cedar: White cedar is preeminently a superior boat timber
and should prove a valuable wood for airplanes as it is
Ught, strong, flexible and free from spUtting. Red cedar
is a strong, very durable wood, but usuaUy very cross-
grained and full of knots. Arbor-Vitce is a variety of
cedar very Ught and springy, fairly free from splitting and
straight-grained. Much used for shingles.

Cypress: Used extensively in boat-building, owing to its dura-
bility, strength and freedom from warping, shrinking and
swelUng. A rather heavy wood and easily spUt.

Poplar: Very Ught, porous, soft wood of considerable tough-
ness and strength, but decays rapidly. Basswood is
sometimes known as ''poplar'' as is also Whitewood. Some
varieties weigh as little as 20 pounds to the cubic foot,
which is but 5 pounds heavier than cork.

Metals Used in Airplanes 131

Redwood (California) : A beautiful, soft, easily worked wood
similar in its properties to Cypress, but lighter.

Spruce: The various spruces, especially Silver and California
spruce, are, as far as known, the most satisfactory woods for
aeronautical use as they are exceedingly strong for their
weight, are very flexible and tough and are probably among
the most elastic woods known. Spruce splits easily, and
the ends where exposed should be tipped with ferrules or
wrapped with wire or shellacked thread as splits once
started spread rapidly.

Sycamore: A very strong, durable, close-grained wood. Light
in weight and exceedingly hard to Split. Excellent for
short struts, propeller blades, control parts, etc.

Whitewood: Also called ^^ Tulip Wood," is a very fine-grained,
soft, durable wood easily worked but brittle and not very
strong.

Willow: Exceedingly strong for its weight and very flexible,
especially when steamed or water-soaked. It should prove
an excellent material for fuselage constructipn and for
propellers.

Metals Used in Airplanes. — ^Although far less stronger
than woods than is generally supposed, yet the various metals
greatly exceed most woods in tensile strength and ultimate
elasticity. Steels, irons, brass, bronzes, aluminmn, monel-
metal, etc., are used considerably in aeronautical construction,
especially in motors and fuselage fittings, and the following
brief descriptions of their compositions and characteristics may
be of interest and value.

Steel, especially alloy steel, such as Vanadium, Chrome, Tung-
sten and Nickel-steels are the strongest metals known,
and steel has been produced that showed a tensile strength
of over 600,000 pounds per square inch. This was, how-
ever, merely experimental steel made in small quantities
in the Krupp works and no steel of such strength has ever
been produced in commercial quantities.

^dy cast-iron, French iron, Semi-steel and Vanadium-iron
are all used extensively for cylinders, pistons, piston rings

132

The A. B. C. of Aviation

and other parts where a splendid wearing surface and

resistance to heat are required without great strength.
Apirial Metal is an alloy of aluminum and lithium of great

strength and very light weight, some examples being only

one and one-hRlf times as heavy as water.
Alumen: An alloy of 88% alimiinum with 10% zinc and 2%

copper. One of the strongest aluminum alloys and readily

forged and milled, but much heavier than aluminum or

many other similar alloys.

TABLE VIII
Strengths of Various Materials

Woods

Name

Alder

Apple

Ash

Bamboo. . . .*

Beech

Birch

California spruce..

Cedar

Cherry

Chestnut

Elm

Hickory

Maple

Oak (live)

Oak (white)

Pear

Pine (Oregon)

Pine (Pitch)

Pine (red)

Pine (white)

Pine (yellow)

Poplar

Spruce (New Eng.)
Spruce (Norway) . .
Spruce (California)

Sycamore

Walnut (black) . . . .
Willow

Pounds

per

Cubic Foot

43
20
43
35

36
43
40
67
43

29
34
24
31
32

• •

Tensile

Strength

in Pounds

11,000

8,000-12,000

7,000-10,000

12,000-14,000

4,000- 9,500

7,000-12,000

« 8,000-13,000

10,000-14,000

8,000-10,000

10,000

7,000-10,000

9,000-14,000

8,000-10,000

5,000- 8,000

3,000- 7,500

5,000-12,000

3,000- 7,000

5,000-10,000

5,000-12,500

12,000-14,000

8,000
10,000

CompresBive

Strength

in Pounds

6,000- 7,000

4,600- 8,000

8,000- 9,000
5,000-10,000

4,000- 6,500
5,000- 6,500
4,000- 4,800
8,000-10,000
8,000- 9,000
5,000- 6,000
8,000-10,000
5,000- 8,000
7,500

6,000- 7,500
3,000- 6,000
6,500-10,000
5,000- 8,000
4,500- 6,000

5,600- 7,000
3,000- 6,000

Strengths of Materials

133

TABLE IX
Strengths op Various Materials — Continued

Metals

Name

Pounds

per

Cubic Foot

Tensile
Strength

Compressive
Strength

Aerial metal

98
184
168
481
526
184
444

• • •

482
152
525
184
485
490

60,000- 70,000

42,660

38,393

92,430

85,320- 86,742

63,990

20,000- 35,000

/ 56,880- 58,302

119,448

41,23^ 63,990

87,000-110,000

56,880

125,000-265,000

99,540-312,840

Alumen

Aluminum

Aluminum bronze

•

Brass

OhromaUiTmiTium

Cast iron

75,000-150,000

CoDDer

Iron (wrought)

Macnalium

Monelmetal

Nickel-aluminum

Steel (allov)

Steel (piano wire)

Name

China Grass

Glue

Hemp

Horn

Ivory

Leather. . . .
Rawhide. . .

Silk

Whalebone .

Miscellaneous
Tensile Strength
in Poimds

22,752
500- 750
6,285-17,000
9,000
16,000
3,000- 5,000
12,000
35,000-62,028
7,600

Argentalium is a patented German alloy of aluminum and
silver. Its specific gravity is 2.9.

Chromaluminum is another patented German alloy of alu-
minum, chromium, etc. Its specific gravity is similar
to the last and it is the strongest known aluminum alloy.

Magnalium: An alloy of aluminum and magnesium, the
latter varying from 2% to 12%. Weighs less than pure
aluminum and is very strong. It resists corrosion about
the same as aluminum and may be easily cast, forged,
machined, rolled and drawn.

134

The A. B. C. of Aviation

Wolframium is an aluminum and tungsten alloy with small
amounts of copper and zinc. It is patented in Germany
and is extensively used in the Zeppelin dirigibles.

Bronzes are all those aUoys m which copper is combmed with
other metals to gain strength or other advantages.

Phosphor-bronze is particularly adapted for wire and cable.
Manganese bronze is nearly as strong as ordinary steel.
Tobin bronze has a strength equal to steel and is used
largely for marine propeller shafts, while Aluminum bronze
is very tough and elastic, but like all the bronzes is too heavy
to be of great value in aviation work.

Monelmetal, a natural alloy of nickel, iron and copper, is as
strong as high-grade steel, resists all known causes of
corrosion save sulphur fmnes and is readily worked, but is
very heavy for aerial work. It is, however, the ideal metal
for boat and hydroairplane uses.

TABLE X

Transverse Strengths of Wooden Bars

(Those marked * were supported edgewise; all tests were with bars supported

at extreme ends)

Name

Elm. . .

Spruce

Elm...

Spruce

Elm...

Spruce
♦Elm...
*Spruce

Elm...

Spruce
*Elm. . ,
*Spruce

Size in Inches

l}i X
1% X
IKe X
IMeX
1 X
1 X
%X

Va X
% X

riex

i}i

i\(

X 12

7i X 12
1 Ke X 12
1 Ke X 12

1
1

Va
He

X 12
X 12
X 12
X 12
X 12
X 12
X 12
X 12

Weight,
Ounces

6Ji

^^
4

3M
3

Load

Sustained,

Pounds

900

900
880
760
450
600
390
475
275
280
176
176

MASS OF MATERIAL TO CONSTRUCT AN AIRPLANE

There is a surprising amount of material of various kinds
necessary to build a single airplane of the more simple kind.

Mass of Material to Construct, an Airplane 135

Materials involving metals of various kinds include the

following:

Nails. 4 4,326

Screws : 3,377

Steel Stampings 921

Forgings 798

Turnbuckles 276

Wire 3,262 feet

Aluminum 65 poimds

The various kinds of wooden material mount up as follows :

Spruce 244 feet

Pine 58 feet

Ash 31 feet

Hickory 1 J^ feet

Other material necessary for the finished plane is as follows :

Veneer 57 square feet

Varnish 11 gallons

Dope 59 gallons

Rubber 34 feet

Linen 201 square yds.

This list of material is exclusive of everything necessary
for the engine alone.

CHAPTER VII

AIRPLANE POWER-PLANTS

Aerial Motors Must be Light — ^Factor Influencing Power Needed — i
Engine Forms — ^Airplane Engine Installation — Standard S. A. £. Engine
Dimensions — Installing Rotary and Radial Cylinder Engines — Cliaract<
of TjTpical American Pre-War Aviation Engines.

One of the marked features of aircraft development
been the effect it has had upon the refinement and i)erfeoti(
of the internal combustion motor. Without question, gasol
motors intended for aircraft are the nearest to perfection
any other type yet evolved. Because of the peculiar demani
imposed upon the aviation motor, it must possess all tl
features of reliability, economy and efficiency now present h
automobile or marine engines. It must also have distinctive*
points of its own. Owing to the unstable nature of the mediuniL
through which it is operated and the fact that heavier-than-air
machines can maintain flight only as long as the power-plant
is functioning properly, an airship motor must be more reliable
than any used on either land or water. While a few pounds
of metal, more or less, make practically no difference in a
marine motor and have very little effect upon the speed or hill-
climbing ability of an automobile, an airship motor must be
as light as it is possible to make it because every pound coimts,
whether the motor is to be fitted into an airplane or into
a dirigible balloon.

Airship motors, as a rule, must operate constantly at high
speeds in order to obtain a maximum power delivery with a
minimum piston displacement. In automobiles or motor-
boats, motors are not required to run constantly at their
maximum speed. Most aircraft motors must function for
extended periods at speeds as nearly the maximum as possible.
Another thing that militates against the aircraft motor is the
more or less unsteady foundation to which it is attached.

136

Aerial Motors Must be Light 137

The necessarily light framework of the airplane makes it hard
for a motor to perform at maximiun efficiency on account of th^
vibration of its foundation while the craft is in ffight. . Marine
and motor car engines, while not placed on foundations as
firm as those provided for stationary power-plants, are installed
on bases much more stable than the Ught structure of an air-
plane. The aircraft motor, therefore, must be balanced to a
nicety and must rtm steadily under the most unfavorable
conditions.

AERIAL MOTORS MUST BE LIGHT

The capacity of Ught motors designed for aerial work per
unit of ma^s is surprising to those not fully conversant with
the possibihties that a thorough knowledge of proportions of
parts and the use of special metals developed by the auto-
mobile mdustry make possible. Activity in the development
of Ught motors has been more pronounced in France than in
any other country. Some of these motors have been very
compUcated, made Ught by the skilful proportioning of parts,
others are of the refined simpler form, modified from present-
day automobile practice. There is a tendency to depart
from the freakish or unconventional construction and to adhere
more closely to standard forms because it is necessary to have
the parts of such size that every quaUty making for reUability,
efficiency and endurance is incorporated in the design.
Airplane motors range from two cylinders to forms having
fourteen, sixteen, eighteen and twenty-four cylinders, and the
arrangement of these members varies from the conventional
vertical tandem and opposed placing to the V form or the
more unusual radial or star motors having either fixed or
rotary cyUnders. The weight has been reduced so it is possible
to obtain a complete power-plant of the revolving cylinder air-
cooled type that will not weigh more than 3 pounds per
actual horse-power and in some cases less than this figure.

If we give brief consideration to the requirements of the
aviator it will be evident that one of the most important is
securing maximum power with minimum mass, and it is desir-
able to conserve all of the good quaUties existing in standard

138 The A. B. C. of Amotion

automobile motors. These are certainty of operation, good
mechanical balance and imiform delivery of power — ^funda-
mental conditions which must be attained before a power-
plant can be considered practical. There are in addition
secondary considerations, none the less desirable, if not abso-
lutely essential. These are minimiun consiunption of fuel
and lubricating oil, which is really a factor of import, for upon
the economy depends the capacity and flying radius. As the
amount of liquid fuel must be limited, the most suitable
motor will be that which is most powerful and at the same
time economical.

Another important feature is to secure accessibiUty of
components in order to make easy repair or adjustment of
parts possible. It is possible to obtain sufficiently light-weight
motors without radical departure from established practice.
Water-cooled power-plants have been designed that will weigh
but 3.5 to 4 poimds per horse-power complete, and in these
forms we have a practical power-plant capable of extended
operation.

FACTOR INFLUENCING POWER NEEDED

Work is performed whenever an object is moved against a
resistance, and the amount of work performed depends not
only on the amount of resistance overcome, but also upon the
amoimt of time utilized in accompUshing a given task. Work
is measured in horse-power for convenience. It will take one
horse-power to move 33,000 pounds 1 ft. in one minute or
550 poimds 1 ft. in one second. The same work would be
done if 330 poimds were moved 100 ft. in one niinute. It
requires a definite amount of power to move a vehicle over
the ground at Vl certain speed, so it must take power to
overcome resistance of an airplane in the air. Disregarding
the factor of air density, it will take more power as the speed
increases if the weight or resistance remains constant, or
more power if the speed remains constant and the resistance
increases.

The airplane is supported by air reaction xmder the planes
or lifting surfaces and the value of this reaction depends upon

Factor Influencing Power Needed 139

the shape of the aerofoil, the amount it is tilted and the speed
at which it is drawn through the air. The angle of incidence
05 degree of wing tilt regulates the power required to a certain
degree as this affects the speed of horizontal flight as well as
the resistance. Resistance may be of two kinds, one that is
necessary and the other that it is desirable to reduce to the
lowest point possible. There is the wing resistance and the
sum of resistances of the rest of the machine such as fuselage,
struts, wires, landing gear, etc. If we assiune that a certain
airplane offered a total resistance of 300 pounds and we wished
to drive it through the ah at a speed of 60 miles per hour,
we can fliid the horse-power needed by a very simple compu-
tation as follows:

The product of: 300 pounds resistance
times speed of 88 ft. per second times 60

seconds in a minute

= H.P. needed

divided by 33,000 foot-pounds per minute

in one horse-power

The result is the horse-power needed, or

300 X 88 X 60

= 48 H.P.

33,000

Just as it takes more power to climb a hill than it does to
run a car on the level, it takes more power to climb in the air
with an airplane than it does to fly on the level. The more
rapid the climb, the more power it will take. Naturally the
resistance is greater when climbing. If the resistance remains
300 pounds and it is necessary to drive the plane at 90 miles
per hour, we merely substitute proper values in the above
formula and we have

300 pounds times 132 ft. per second times
60 seconds in a minute

= 72 H.P.

33,000 foot-pounds per minute in one

horse-power

140 The A. B. C. of Aviation

The same results can be obtained by dividing the product
of the resistance in pounds times speed in feet per second by
550, which is the foot-pounds of work done in one second to

equal one horse-power. Naturally, the amount of propeller
thrust measured in poimds necessary to drive an airplane must
b" the resistance by a substantial margin if the

. cUmb as well.

Airplane Engine Forms

AIRPLANE ENGINE FORMS

Inasmuch as numerous forms of airplane engines have
been devised, it would require a volipie of considerable size
to describe even the most important developments of recent
years. As considerable explanatory matter has been given in

Fig. 64. Th« Anzaiii Siz-Cyliuder Fixed Radial Engine.

preceding chapters and the principles involved in interna!
combustion engine operation considered in detail, a relatively
brief review of the features of some of the most successful
airplane motors should suffice to give the reader a complete
enough landerstanding of the art so all types of engines can

142

The A. B. C. of Aviation

be readily recognized and the advanU^es and disadvantages
of each type imderstood,

Aviation engines can be divided into three rmun classes.
One of the earUest attempts to devise distinctive power-plaat
designs for aircraft involved the construction of enpnes utilizing

Fig. 65. Air- and Water-Ciwled Aviation Power-Plants. A. Renault I
Cylinder. B. Gnome Rotary. Below Six-Cylinder Type.

a radial arrangement of the cylinders or a star-wise disposition.
Among the engines of this class may be mentioned the Anzani,
•in its various forms. These are air-cooled. Engines of this
type have been built in cylinder numbers ranging from three
to twenty. While the simple forms were popular in the early

Airplane Engine Installation 143

days of aviation engine development, they have been succeeded
by the more conventional arrangements which now form the
largest class. The reason for the adoption of a star-wise
arrangement of cylinders, shown at Fig. 64, has been previously
considered. Smoothness of running can only be obtained by
using a considerable number of cylinders. The fundamental
reason for the adoption of the star-wise disposition is that a
better distribution of stress is obtained by having all of the
pistons acting on the same crank-pin so that the crank-throw
and pin are continuously under maximmn stress. Some
difficulty has been experienced in lubricating the lower cylinders
in some forms of six-cylinder, rotary crank, radial engines, but
these have been largely overcome so they are not as serious
in practice as a theoretical consideration would indicate.

Another class of engines developed to meet aviation
requirements is a complete departure from the preceding class,
though when the engines are at rest it is difficult to differentiate
between them. This class includes engines having a star-wise
disposition of the cylinders but the cylinders themselves and
the crank-case rotate and the crank-shaft remains stationary.
The important rotary engines are the Gnome, the Le Rhone
and the Clerget. By far the most important classification is
that including engines which retain the approved design of
the types of power-plants that have been so widely utilized in
automobiles and which have but slight modifications to increase
reliability and mechanical strength and produce a reduction
in weight as outlined in Fig. 63 and in Fig. 65. This class
includes the vertical engines such as the Hall-Scott four-
cylmder; the Mercedes, Benz, and Hall-Scott six-cylinder
vertical engines and the numerous eight- and twelve-cylinder
V " designs such as the Curtiss and Renault.

AIRPLANE ENGINE INSTALLATION

The proper installation of the airplane power-plant is more
unportant than is generally supposed, as while these engines
^re usually well balanced and run with little vibration, it is
necessary that they be securely anchored and that various
connections to the auxiliary parts be carefully made in order

Engine

Supporting

Plate

Landing
Gear Sfruis-^''.

Fig. 66. Anzani Ten-Cylinder Engine Installed in FuselaEC.

installed determines the method of installation to be followed.
■As a general rule the six-cylinder vertical engine and eighth

Airplane Engine Installation 145

Under " V " type are mounted in substantially the same
ly. The radial, fixed cylinder forms and the radial, rotary
Under Gnome and Le Rhone rotary types require an en-
rely different method of mounting. The usual form of
igine bed for a fixed cylinder engine is shown at Fig. 68.

In a number of airplanes of the tractor-biplane type the
ower-plant installation is not very much different than that
rhich is fomid in automobile practice. The -illustration at top

Fig 67 Showmg Engme Installal

Monocoque Fuselage

trf Fig 70 IS a very clear representation of the method of
Biountmg the Curtiss eight-cylinder 90 H P engine in the
fuselage of the Curtiss tractor-biplane v,]avh is so generally
Used as a traimng machine It will be observed that the
"Jel tank is mounted under a cow 1 directly behind the motor and
that it feeds the carburetor by means of a flexible fuel pipe. .
'^ the tank is mounted higher than the carburetor, it will feed
''Oat member by gravity. The radiator is mounted at the front
^Bd of the fuselage and connected to the water piping on the

146 The A. B. C. of Aviation

motor by the usual rubber hose connections. An oil pan is
placed under the engine and the top is covered with a hoot!
just as in motor car practice. Panels of aluminum (not shown
in cut) are attached to the sides of the fuselage and are sup-
plied with doors which open and provide access to the car-
buretor, oil-gauge and other parts of the motor requiring

Fig. 68. En^e Bed ConBtTuctlon in Typical Germaa Aitplane.

inspection, A complete installation with the power-plant
enclosed is given at Fig. 67, and in this it will be observed
that the exhaust pipes are connected to discharge members
that lead the gases away toward the rear of fuselage. In
the engine shown at top of Fig. 70 the exhaust flows directly
into the air at the sides of the machine through short pipes
bolted to the exhaust gas outlet ports. The installation of the"^

radiator just back of the tractor screw insures that adequate
cooUng will be obtained because of the rapid air flow due tft
the propeller slip stream. The engine installed in the airplaEa
shown in Fig. 70 B is a four-cylinder type and the radiatoj:-
is mounted above the motor mstead of in front, as depicte<3
in Fig. 70 A.

STANDARD S. A. E. ENGINE BED DIMENSIONS

The Society of Automotive Engineers have made effor^i^s
to standardize dimensions of bed timbers for supporting powe im-
plant in an airplane. Owing to the great difference in lengfcl
no standardization is thought possible in this regard. Ttt»-<
dimensions recommended are as follows:

Diatance between timbers 12 in. 14 in. 10 i.**

Width of bed timbers I J^ in. Ifi in. 2 i*3

Distance between centera of bolts 13^ in- ^^H "n. ISLKi

It will be evident that if any standard of this nature wei*^
adopted by engine builders that the designers of fuselage
could easily arrange their bed timbers to conform to thes^
dimensions, whereas it would be difficult to have them adhere

Standard- S. A. E. Engine Bed Dimensions 149

to any standard longitudinal dimensions which are much more
easily varied in fuselages than the transverse dimensions are.
It, iiowever, should be possible to standardize the longitudinal

Vertical Radiator

Top
Plane^

Fig. 70 B. How Airplane EogiiieB Are Installed in Fuselage.

positions of the holding down bolts as the engine designer
would still be able to allow himself considerable space fore-
and-aft of the bolts.

150

The A. B. C. of Aviation

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iaUing Rotary and Radial Cylinder Engines 151

[STALLING ROTARY AND RADIAL CYLINDER ENGINES

len rotary engines are installed simple steel stamping
)iders" are attached to the fuselage to hold the fixed
shaft. Inasmuch as the motor projects clear of the
;e proper there is plenty of room back of the front spider
:o install the auxiliary parts, such as the oil pump, air
and ignition magneto and also the fuel and oil containers,
agram given at Fig. 69 shows how a Gnome ''monosou-
engine is installed on the anchorage plates ; and it also
5S clearly the f)iping necessary to convey the oil and fuel
so the air piping needed to put pressure on both fuel
I tanks to insure positive supply of these liquids, which
e carried in tanks placed lower than the motor in some
itions. The simple mounting possible when the Anzani
linder radial fixed type engine is used is given at Fig. 66.
ont end of the fuselage is provided with a substantial
i steel plate having members projectmg from it which
e bolted to the longerons. The bolts that hold the two
of the crank-case together project through the steel
and hold the engine securely to the front end of the
;e

c. — For a more complete discussion of airplane power plants the reader
^ to '^ Aviation Engines" by Pag^, price 13.00, which can be obtained
8 Norman W. Henley Pub. Co., 2 West 45th Street, New York City.

CHAPTER Vin

AIBPL&HE PROPELLER COHSTRDCTION AND ACTION

When Screw WoAa in Air — HaQieiiutical Contideratioii rf Propeller Pitdi—
Propeller Definitioiu — Propeller Hanuf actnring Practice — Theories of Scmr
Propeller Action — How Propellers are Balanced — The Disc Theory— Tlie
Blade Theory.

The principle of the screw was applied by Archimedes, the
Grecian mathematician, in raising water as early as 200 b. c,
and the screw or helical rotating propeller has been associated
with methods for the propulsion of aerial craft for four or five
centuries. The original screw propeller was of the single
worm type, having but one thread, and could hardly be com-
pared with the present form. That we may properly appre-
ciate the fimctions of the screw propeller we have an excellent
demonstration of the principles involved in the bolt and nut,
with which all are familiar.

A screw is a cylinder having a spiral ridge or thread around
it, which cuts at a constant oblique angle all the lines of a

Fig. 71. Diagrams Explaining Pitch of Aerial Screw Propeller.

surface parallel to the axis of the cylinder. A hollow cylinder,
called a nut, having a similar spiral within it is fitted to move

Airplane Propeller Construction and Action 153

freely upon the thread of the solid cylmder as shown at Fig.
71 A. For simplicity we will consider that there are four
threads to the inch. Obviously, if the nut was held stationary,
in four complete turns the screw would advance or recede an
inch if the screw were turned toward the right or left. On the
other hand, we will assume that the nut is so held that it can
travel only back and forth and not around when the screw is
turned. Four complete turns of the screw would produce a
movement of one inch, one complete turn would move the nut
one-quarter inch. This distance is the pitch of the screw, as
the definition is : The pitch of a screw is the distance through
which the screw would advance in one revolution, provided
that it revolved in an unyielding medium, such as a soUd nut.

It will be evident that if the thread of the bolt were of
such depth to offer sufficient area that considerable resistance
would be offered to its backing in or coming out of a more
flexible medium in which the bolt was submerged, such as
water, that the water surrounding the threads would act to a
certain extent as a nut, and assuming that this did not move
either backward or forward, as would be the case were the
nut of resisting material held immovable, it may be seen that
revolving the bolt would tend to exert a thrust which would
produce either forward or reverse movement of the bolt.
This is the principle of the screw propeller whether^ it operates
in air or a denser medimn, such as water. The less the density
of the fluid in which the propeller is submerged, the greater the
area of blade or thread siuiace necessary to exert the same
thrust.

If the screw is mounted in such a way that it is continu-
ously revolved, it will produce a continuous movement. For
instance, assiuning that the bolt has a pitch of one inch and
that it worked in an elastic medium less resistant than soUd
substances of which nuts are usually made: As it is tmned
there would be two effects: the bolt would move forward, and
''he fluid in which it turned would be pushed backward. Thus
the effect of screw propeller would be duplicated. Because
turning the bolt pushed back the elastic substance in which it
^85 submerged as well as producing forward movement of

154 The A. B. C. of Aviation

the bolt, it would not advance as much per revolution as though
it were working in an unyielding medium; for instance, while
the pitch was one inch, and theoretically considered, the bolt
should move forward a distance corresponding to the pitch,
because of the reaction, the degree of movement which actually
takes place would be considerably reduced.

For considerations of balance, an aerial propeller is not
based on the design of a single thread screw but on a double,
triple or quadruple thread type, depending on the niunber of
blades.

WHEN SCREW WORKS IN AIR

In the case of a screw working in air, however, we are
concerned with very different conditions from those found in a
rigid combination such as we have just instanced. Air is a
highly rarefied medium, the density being only one eight-
hundredth that of water, and one six-thousandth that of steel.
A perfect liquid is one whose molecules are perfectly free to
move over one another with the sUghtest disturbing force—
and air approaches very near to such an ideal Uquid. With
a screw working in such an elastic and accommodating medium
it will not be surprising to find a certain amount of air slip
beneath the blades so that the space covered per revolution is
always something less than that represented by the geometric
proportions of the screw blade. (See Fig. 71 B.) The axial
space covered by a propeller for the incoming air is given
an added velocity in passing through the propeller disc. At
zero slip no additional velocity and no rearward momentum
is imparted to the incoming air stream, and as. a consequence
the thrust will be zero and there will be no true wake stream
beyond that due to skin friction. The advance per revolution
at which no thrust is obtained is termed the mean experimental
pitch or zero thrust pitch of the propeller. It is a value
found experimentally by artificially driving the screw through
the air at increasing velocities till the point is reached at which
there is no thrust. The experiment is usually done on a large
whirling arm or in a wind tunnel, but an approximate value
can be found quite easily by placing the estimated no-lift line

Mathematical Consideration of Propeller Pitch 155

on the blade section at two-thirds full diameter, thw bein^ at^
ornear, the center of pressure of the blade. Its value will vaiy
slightly along the blade, but a very good approximation to the

Backof Blade

Leading Edqe

'Copper Tip

H& 71- How to Start Bngjiie Fitted with Aerial Screw That Turns Left
Hand, or Aati-dockwise, When Viewed from Front of Airplane. If con-
sidered from Viewpoint of Pilot, This is a Right-Hand Screw.

fijtperimental value may be found by taking the section thus
'iefined as a criterion.

MATHEMATICAL CONSIDERATION OP PROPELLER PITCH

The geometrical blade pitch face is the aerial span of one
twist of a helical Une of constant angularity and radius: each
revolution is termed its mean effective pitch. It is a function
of the thrust of any instant and varies with each manoeuvre
of the pilot. Thus, under climbing conditions, the effective
pitch may drop 50 per cent, of its value in level flight, the slip,
of course, increasing at the same rate. An analogous case
"lay be found in the slip of an ordinary bolt and nut, as often

156

The A. B. C. of Aviation

happens in driving against a heavy load. In the case of the
air screw, however, the thrust is obtained by reason of the sUp
of air under the blades, so, equal to that at the section taken.
The fact that only a small fraction of a complete twist actually
exists in the aerial propeller does not affect the argument as
the pitch is quite independent of the blade width, but is a
function only of the angle and radius of rotation. It usually
varies along the blade and in most cases gets greater towards
the boss, so that the blade face is not part of a true helix.
It is necessary, then, to state precisely the section at which
measurement is to be made. The general rule is to take the
blade angle at two-thirds full propeller diameter as a basis

Fig. 73. Dkgram Sboiriiig Some Points of KvAtX Screw Design Conddered
HathenuticaUy.

for calculation. The value so found is the blade pilch, or
simply the pitch, as ordinarily referred to by propeller makers
and dealers, and it is the figure stamped on the boss. It is
very important to remember that this is a purely geometrical
quantity, depending only on the angles and proportions of the
blade, and is not connected in any precise way with the effective
pitch or mean experimental pitch.

Theories of Screw Propeller Action 157

Tlxe following is a key to the symbols used in the illus-
tration, Fig. 73:

V = translational velocity (ft. per sec).
h = inflow velocity forward of blades.
h = additional velocity rearwards.
h = slip velocity.
D = full diameter of prop,
i = diameter at any section,
n == number of revolutions per second,
a == angle of attack between no-Uft line and direction of

relative wind.
9 =?= helix angle of relative incoming air.

A ^ blade — ^face angle at any section.

V
Po = mean effective pitch = — .

Po = experimental mean pitch or zero thrust pitch.
Pp = blade face pitch = % tt D tan A.

Propellers are made in two, three- and four-blade types, the
former being the most popular. In order to hold down or
Utilize the full power of a large engine, it is sometimes neces-
sary to use a three- or four-blade type because a two-blade
tonn, suitable to absorb the power, would need excessive pitch
or dianieter. A two-blade is the most desirable as it is the
^iest to build and balance and the most efficient.

THEORIES OF SCREW PROPELLER ACTION

The many theories regarding the principles which govern
propeller action may be grouped in either of two classes* To
the first may be assigned those which consider the action of the
screw upon the medium in which it is submerged, and from
the movement of the elastic medium deduce the reaction upon
the propeller. To the second class belong the theories which
consider only the action of the medium upon the propeller.

THE DISC THEORY

The "disc'' theory is a notable example of the first class,
^^ considers that the propeller displaces a quantity of th^
niedium in which it tunls equal to the propeller diameter/ and

158 The A. B. C. of Aviation

that given a given amount of fluid having a certain change of
velocity impressed upon it, the reaction resulting can ap-
parently b^ calculated at once from the known density of the
fluid. This method would possess a beautiful simpUcity if
we knew the exact effect of a propeller upon the fluid it passes
through, and if the propeller blades were frictionless. Some
authorities have assumed that a screw propeller gave to a
coliunn of fluid having a sectional area equal to the disc swept
by the propeller a stemward velocity corresponding to the
sUp, but it would appear that in theories of the first class a
change of pressure of the medium in motion is of just as much
importance as a mere consideration of change of velocity of
the fluid acted upon.

THE BLADE THEORY

In the "blade" theory, typical of the second class, the
face of the propeller blade is treated as if it were made up of a
number of small inclined planes advancing through the water,
and it is this hypothesis that most authorities seem to favor.
As will be obvious, if the blade surface were treated as an
incUned plane, the medium could be considered as imposing
a thrust upon the surface which would vary with the density
of the mediiun and the angle of inclination of the plane as the
blade moved through it. Despite the variance of theories it is
evident they all bring out the same fact, and that is, that
rotation of a screw in a suitable medium will produce movement
of both screw and fluid in which it is submerged. If the screw
is held so that it can move only in a rotary direction the
column of fluid it sets in motion will only move. If the
screw is operating in an immovable medium, the screw will
move in a direction parallel to its longitudinal axis. If both
screw and fluid are free to move, the degree of movement will
depend upon the "slip'' between the screw and the medium in
which it works.

PROPELLER DEFINITIONS

Before considering the constructional features of propellers
used for the propulsion of aerial craft, it will be well to give
some brief definitions. A right-hand propeller is one that

Propeller Definitions

159

when viewed from the rear, turns with the hands of a watch
when driving the machine to which it is fitted ahead. Under
similar circimistances a left-hand propeller turns against the
hands of a watch to produce forward movement. If a right-
hand propeller is turned toward the left, the effect will be to
produce a reverse movement of the object to which it is
applied. The ''face'' of a blade is the practically straight
back surface, that which drives the fluid back while the screw
is going ahead. The ''back'' of the blade is the side opposite
the face, and care must be taken to avoid confusion of terms,
from the fact that the "face" of a blade is aft and the "back"

''Hub Bore " " ^Leading Edge

Section A-A Section BB SecHonOC Section D-D Section E-E Section F-F

Pig. 74. How Propeller Blade is Shaped at Various Stations along Blade.
Note Aerofoil Section at Different Points and Lessened Angle of Incidence
as the Tip is Approached.

forward. The back of the blade is usually a cambered surface,
as shown at Fig. 74.

"The leading edge" of a blade is the edge which cuts the
fluid first when the screw is turning ahead, while the "following
^dge" is opposite the leading edge. The "leading edge" is
Usually curved more than the "following edge." The "di-
toieter" of a screw is the diameter of the circle described by
the tips of the blades. In symmetrical two- and fom'-bladed
Screws it is simply the distance from the "tip" or outermost
?art of one blade to that of the opposite member. The
'pitch" at a given point of the face is the distance from the
ixis of the shaft which an elementary area of the face at the
ioint, if attached by a rigid radius to the axis, would move
luring one revolution, if working in a solid fixed nut. The
:>itch may be different at every point of the face. If it is the

160 The A. B. C. of Aviation

same at all points we say that the pitch is "uniform.'' If the
pitch is greater along the following than the leading edge, it is
said that the pitch "increases axially/' and if it grows greater
as we leave the center we say the pitch "increases radially.''

The "area" or "developed area" of a blade is the surface
of its face, and the "blade area" of a screw, sometimes called
its "heUcoidal area," is the amomit of face surface of all its
blades. The "disc area" of a propeller is the area of a circle
described by the tips of its blades. The "boss" of a screw
is the cyUndrical center to which the blades are attached, and
the "hub" is the metal clamp by which it is attached to the
revolving shaft. When a propeller is working with "slip"
it advances during each revolution a distance less than the
pitch, the difference between its actual advance and the pitch
indicates the amoimt of slip. The "speed" of the screw is
the distance it would advance in a unit of time, supposing it
to be working in a soUd nut. This is obviously" equal to the
pitch of the screw multipUed by the number of revolutions
per imit of time.

The empirical rule that is followed usually in designing
either wood or metal propellers having two blades for use in
air is- as follows : The diameter should be as large as possible
compatible with the Umits of design; the blade area should be
from 10 to 15 per cent, that of the area swept; the pitch should
be approximately four-fifths the diameter, and the speed of
rotation should be small, never more than 1500 revolutions
per minute. As the speed of rotation is increased, the diameter
must be reduced. Maximiun thrust effort will be obtained with

N f

large diameter and low speed.

PROPELLER MANUFACTURING PRACTICE

Airplane propellers are usually made of wood because this
material is the one that has the greatest strength in proportion
to its weight and has been found to be the best adapted.
Commonly used woods in American manufacturing practice
are Honduras mahogany, birch and white oak. Spruce,
maple, cherry, ash and poplar are sometimes used. English
practice favors mahogany and black walnut, their preference

Propeller Manufacturing Practice 161

seeming to be for the latter. Spruce is used for the manu-
facture of propellers for small engines to some extent. This
wood, has the advantages of being Ught and strong, as well as
easy to glue, and climatic conditions do not aflfect it imduly.
This wood is seldom used in propellers for engines of more
than 60 H.P. Propellers to absorb 100 H.P. have been suc-
cessfully made with alternate laminations of maple and spruce,
with the layers so arranged that the hard wood comes on the
outside to better resist the compressive eflfect of the metal
hub plates and flange.

Mahogany is comparatively light and is not dijEcult to glue.
It is a soft wood, however, and easily marred. Quarter-
sawed white oak has a high tensile strength, but unless abso-
lutely dry stock is used some trouble will be encountered
with the glued joints. The reason the quarter-sawed is used
in preference to the plain oak is that the latter is apt to develop
season cracks. In propellers for engines of 200 H.P. or more,
birch has been used very successfully because it is tough
and strong in resisting tensile strain and is not unduly heavy.
Its disadvantages are that it is affected easily by changes of
weather and will warp or check, especially when thin sections
are used. For extreme climatic conditions, such as encountered
on the Mexican border, mahogany or poplar has given good
satisfaction. Ash is not recommended if mahogany or walnut
is obtainable, because it is difficult to laminate it or work it on
account of its tendency to splinter. Quartered white oak is an
excellent ndafbrial for use in connection with propellers for large
engines.

Any airplane propeller, except the very small ones used for
Operating fuel feed piunps, electric dynamos for radio, etc.,
^ made up of a niunber of laminations. In the early days,
^lane propellers were made from a soUd piece of timber,
out this practice was discontinued on account of the difficulty
^ keeping these in condition. A laminated propeller will not
^arp or draw out of shape as quickly as a one-piece propeller
^11. Each lamination is balanced separately, and as the block
|rom which the propeller is to be shaped is built up in the press
^t is customaiy to lay the heavy end of one ply alongside the

162

The A. B. C. of Aviatum

light end of the next layer and in this way a fairly well-balaneeci
propeller blank is obtained.

There are two methods of gluii^ up the laminations.
Straight materia! may be glued into a rectai^ular block and

"GaJgeB/ocks ^°'" l^mi nation sa re Se+forGluing
/Trailing Edge

•Leading Edge

Copper Tip'

Fig. 75- How Laminatiotts ore GIned Together to Moke Block fiom VUdi
Propeller is Fonned.

roughly band-sawed out to shape, or it may be made of lamina-
tions that have been sawed, rough bored and aligned for pitch
by means of templets as shown at Fig. 75. The best ca» is

Fig. 76. Special Latbe for Tuming Out Propellen.

Propeller Manufacturing Practice 103

;. 77. Installation of Direct Driven Tractor Screw Which Turns

taken in the gluing process, and good hide glue to which various
chemicals are added for water-proofing purposes is used.
Needless to say, the wood must be absolutely dry before
gluing, and the laminations must be firmly clamped together
in a powerful press while the glue is setting.

There are various methods of shaping the propeller bladeSj
and a number of ingenious machines have been developed to
to do this work. The machine commonly used is a duplicating
lathe, as shown at Fig. 76, which is a modified form of axe-
handle machine, A model propeller is used over which the
cam that regulates the travel of the cutters operates, and this
shapes out the propeller to nearly its finished dimensions.

^^s^^\^Vv'^v\^

Fig. 78. Propeller Hub of German Design is of Light but Strong ConEtruction.

After this roughing out process, the propellers are hung along
a wall or stored in special rooms for a few weeks so that the
wood may adjust itself to its new shape and take a final set.
The finishing is done by bench workers who work the blades
to size with draw knives, spoke shavers, small planes, wood
rasps and hand scrapers.

After the propeller is finished, it is carefiilly sand-papered
and polished, the bore is reamed to fit the hub and the finishetl
propeller is tested for balance and alignment. A high-grade
piano finish is put on in the finishing department, where a coat
of wood filler is applied and well rubbed down, this being
followed by the application of three coats of water-proof spar

Propeller Manufacturing Practice

Trailing Ec/ije
StKl Sqaara ■>[

<.-Wde!hrtsf Blade

Smooth
■ Cast iron
ChecAihg

Method of Checking Pitch of Bla

des

,.,'Ffadlus Lines

X" "^

-•y

( rP^

<■ 6'-5

_^.\

„.,

\ K J

Const,

•cfior.

Unf

\^oll for

Station * 1 "B "I *f *S '6 »7

- fifi-

Layout- of Top of Checking Table

^- 79. How Propellers are Tested for Balance and Blades Checked for
Pitch at Various Stations.

106 The A. B. C. of Amotion

Fig. So. Stand for Balancing Propellers.

How Propellers Arc Balanced

167

famish. Some propellers are tipped with sheet metal, which
tips are securely riveted into place in order to strengthen the
ihia propeller blade at the point, and also to reduce the dangCT
if splitting. Sometimes propeller blades are covered with a
ayer of airplane linen, which is stretched tightly over the tips
.nd given three or four coats of "dope," which shrinks it
ightly and makes it stick to the blade. The balance of a
tropeller should always be checked after tipping.

HOW PROPELLERS ARE BALANCED

i. propeller is balanced by the simple fixture comprising a
t Fig, 79 A, having a pair of straight edges which

Slower Speed Than Engine by Reduction Gearing.

ipport the mandrel and which are carried high enough to
How the propeller to rotate clear of the floor. The supports
lould be adjustable so they can be accurately leveled. A
ropeller should balance in any position in which it is placed,
e., it should not rock back and forth or move when it hi

la^i^fl

feon placed in any position. Endeavor is always made to

Vjalaoce propellers in a room free from air currents. Each

Tilade should be balanced in vertical, horizontal and 45 degrees

ieach side of the vertical position. The entire propeller should

I be rotated so that each blade will receive both top and bottom

Hob Flange

Speed Reducing Gear

Ball Bearing
Supporting Propeller Shaff-

Space 'for CrankShaft Gear

Fig. S2. Showing Airangement of Geared Down Propeller Drive.

]>osition. If a propeller does not balance, it is usually because
there is more wood on one side than on the other. Copper-
tipped propellers are easily balanced by peening in the soft
metal, filling the depression with solder and scraping off the
surplus metal until the proper degree of balance is obtained.
Untipped propellers are balanced by removing the surplus
rial- This is always done by taking wood from the back

How Propellers Are Balanced 169

of the blade, and extreme care is necessary not to destroy the
contour of the section.

After the propeller is balanced, it is stored away until
needed. Before being used, it is customary to check the pitch
of each blade to make sure that they coincide at similar stations.
A station is merely a point on the blade at intervals of six
inches from the hub center. The blades are checked with a
bevel protracter which gives the angle, or by the use of two
squares, in which case accurate measurements are taken. A

Re. 83. Sectional View of Airplane Engine Having Reduction Gear Drive for
Propeller. Engine Runs et 3000 R.P.M. in Order to Develop Maiimnm
Power; Aerial Screw Turns at igoo R.P.M. for Greatest Efficiency.

cast-iron surface plate, accurately planed. Is used for this purpose,
aa it is nec^sary to have a true surface to make accurate com-
parisons possible. When a bevel protractor is used, the pitch
should not vary more than a quarter of a degree. It is im-
portant that both propelier blades be the same length in order
to secure a well-balanced job. As propellers are designed the
pitch is not the same at each station, so in checking up the
same station is chosen on each side of the blade, generally at
the widest portion, and the measurements taken at that point.
Propeller maintenance is an important point to consider.
Propellers should be cleaned and poUshed with shellac and oil

170 The A. B. C. of Amotion

at the conclusion of each day's flying. The polish is compc
of about six parts of shellac to one of linseed oil, which is
pUed to the propeller with a cloth and vigorously rubbed
glassy finish with a piece of cheesecloth. If the machine i
stand out in the sun or weather for any length of time,
propeller should be covered with a canvas cloth or with e
cially made boot to fit it. This prevents checking of the vi
and warping or bUstering of varnish due to the heat. As 1
as the finish is properly maintained, the propeUer is not
to absorb moistmre.

CHAPTER IX

AIRPLANE EQUILIBRIUM AND CONTROL PRINCIPLES

I^actors Regulating Equilibrium and Stability— Why Small Control Surfaces
are so Effective — Control Methods of Early Airplianes — Standard Control
Systems of To-day — The Fuitction of Balanced Control — ^Why the Airplane
is Banked in Turning — ^Instruments for Navigating Airplanes — Suggestions
for the Student in Flying— Run Motor Slowly to Warm It— How to Take Off-
How to Attain Altitude and Handle Machine — ^Precautions When Landing —
Danger in Stalling — Control in Making Ttims — ^Flying Learned Only by
Practice — ^Important Hints.

The reader is undoubtedly familiar, in view of the
latter previously discussed, with the general principles
ivolved in airplane sustentation and balance. The various
arts of the machine have been outlined fully and the f imctions
f the different control elements should be well recognized,
before describing the two most popular control systems it
lay be well to go a Uttle deeper into the subject of airplane
^abihty. Aircraft must be capable of movement in three
irnensions, and it will be seen by reference to Fig. 84 there
»"e really three axes about which the airplane may move.
'lie longitudinal axis indicated by the line XX is the one
'^sd passes from the front to the rear of the fuselage. The
i.t€ral axis mdicated by the line YY passes, from wing tip to
ing tip. The vertical axis ZZ passes through the center of
^a,vity of the machine and is the pivotal point about which
^e yawing movement takes place. This movement is
^xitrolled by the vertical rudder which is incUned to one side
t^ the other so that the air pressure against it wiU cause the
^il of the machine to swing toward the side opposite to that
^ which the rudder is incUned. The lateral or Y axis is the
^e about which a pitching movement takes place, this being
^ntrolled by elevator flaps which regulate the rise and fall of
■^e tail about the axis YY. Whenever the ailerons are
'P>erated a rolling motion of the machine takes place with the
^^ XX as the pivotal line for the lateral movement.

172

The A. B. C. of Aviation

The important condition that must be observed to secure
the steady support of any plane body in the air is that there
be a coincidence between the centers of pressure and gravity,
or at least that these have such relation to each other that
any additional forces brought into play be coimterbalanced.
As we have seen, the effect of air in motion under an inclined
cambered plane, or the motion of an aerofoil through the air, is

XX ■ Pivotal Line for Lateral Movement
YY» *» .. - Pitching "

Z ZZ- •• « -» Yawing

YAxis

^Vertical Rudoler Controls
movements to Right (ht .,
Left or wiZ Axis

Ailerons control '
movements of Wing
tips up or down on X Axis

X = Axis about which Lateral Movement takes place
Y » " " " Pitching " • »

Z ■ " " •» Yawing " *» *»

X Ax/s

'Elevator Flaps control
rise anal fall or movemtnte
on y Axis

Fig. 84. A Diagrammatic Representation of the Three Axes about Which
Movement of an Airplane in Flight May Take Place.

to create certain positive and negative pressures which up to ^
certain point vary as the angle of incUnation of the plaa^
with the relative wind and the velocity of the plane movemen^^
through the air. Some of the conditions which must be otF
served in securing equiUbrium are clearly outUned at Fig. 8^ ^

As the diagram at C, Fig. 86, shows, there are four different'
forces acting upon an airplane while it is in flight. Th^^
attraction of gravity, which is represented by the total weight^
of the machine, acts downward from the center of gravity 0^
the body. The lift is the force opposed to and equal to
exceeding the weight force and acts in the opposite directio

upward. This lift is, of course, created by the supporting'

nt*

Airplane Equilibrium and Control Principles 173

action of the wings or some of the other parts of the machine
and acts upward through the center of pressure. As has been

Cenftrof
.,- Gravity

rC.6

Poinfof
Support

Wtighf

RS^

B
Weight kfoveal

Center of Prtasurf'' ^-Center of

D Gravity

Supporting Plane

Aileron /
Neutral-'

Center of Lift''
or Pressure

Plane in Normal
Flying Position

•Tractor
Screw

^^- Center of
Gravity

\ Aileron
'^Neutral

Tilted up to depress
Hi is tip tilted down
^to raise this tip

Weight

S* 85. At the Bottom is Seen the Effect of the Opposite Forces of Lift and
Gravitation to Which an Airplane is Subjected in Normal Flight. The
Diagrams at the Top Show the Effect of Shifting the Center of Gravity
Relative to the Point of Support.

reviously explained, there is a certain resistance offered by
le whole machine which is due to both the unavoidable

k 10' ^

.5'- >k- 5' ^

'10'-

1-2^0"-^ 7^6'

•1

^fOO/bimtight

too lb.,

100 Uk

:t-

fulcrum"-^ ^T-^-^ Levi

^ Showing Principle of Leverage Involved in Airplane Control

/ Motor.

Traction - Resistaoce
lift - Wkight

'action

Airplane in Normal Flying Position

f Weight

^Q. Illustrating the Action of Traction, Resistance, Lift and Gravity On An
Airplane. At the Top Is An Illustration of the Part Which Leverage Plajrs
^<^ Airplane Control.

174 The A. B. C. of Aviation

resistance met with in forcing the lifting surfaces through the
air and the parasitic resistance (which can be reduced by
skilful designing) which is due to the non-lifting portions of the
machine, such as the struts, landing gear, bracing wires and
skin friction of the fuselage. This force is represented by the
Une of resistance and it acts through the center of resistance.
This must be overcome by the traction or pull of the propeller
in a tractor biplane and by the push or thrust of the propeller
in a pusher type machine, which force acts through the center
of thrust. When an airplane is in normal horizontal flight,
it is evident that the traction must equal the resistance or be
greater than the resistance and the lift must equal the weight
or be greater than the weight. To secure a balance or have the
machine in a condition of equilibrimn at all times, the forces
must meet at the center of gravity of the airplane or the
disposition of the centers of thrust, gravity, pressure and
resistance in relation to each other must be so that balancing
forces will be present. It is not within the purpose of a discus-
sion of this nature to go very deeply into the subject of forces
and movements, but it may be well to seciure an understanding
of some of the simpler rules that must be considered in con-
nection 'with the arrangement and location of the control
siuiaces.

We can assume that there is one point on the airplane
structure where the sustaining effect will be centered and, as
shown in the lower portion of Fig. 85, this would be on the
Une of the main wing spars at the center of the fuselage and is
usually known as the center of lift or pressure. The center
of gravity is that point in a body where all other parts acted
upon by the attraction of gravity balance each other about it in
every position. The force of gravity acts in parallel lines
on every part of a body regardless of its shape and therefore
the center of gravity must be that point through which a
resultant of all these parallel forces is directed in every posi-
tion of the body. If one considers a ball or sphere of uniform
density, the center of gravity would be exactly at its center.
The location of the center of gravity in irregular shaped
objects depends upon where the greater portion of the weight

Factors Regulating Equilibrium and Stability 175

es. Naturally it will be nearer the heavy parts than the light
>arts. If one considers the sketch of the airplane shown at
•"ig. 86 C, which shows a side view, the approximate location
rf the center of gravity may be readily determined. It is near
he front end of the machine because the power-plant and fuel
)anks, which are the heaviest parts, are carried at that end.

FACTORS REGULATING EQXnLIBRIUM AND STABILITY

To secure stable equilibrium of any body the point of sup-
port must coincide with the center of gravity. In considering
the support of a body having three dimensions we must
accept the base at that area on a horizontal plane which is
3oinprehended by Imes joining the extreme pomts of contact.
Thus, the base of a box would be represented by a rectangular
irea while the point of support of a steel ball on a non-yielding
lurface would be a point. The larger the base the more
table a body is. The slightest touch will set a ball roU-
Qg, while it takes considerable effort to disturb the equi-
^brium of a box.

If a vertical Une drawn from the center of gravity, which
ne is known as the line of direction, falls within the base
f the body, it is said to be in stable equilibrium. If it falls
t or near the edge or base of the body, it is in imstable equi-
brium, and the sUghtest force will cause overturning. This
oint can be readily demonstrated by tipping a box so that it
all stand on one of its edges mstead of on its side or base. If
he Une of direction falls outside the base, the body is not
upported.

What is true of a body supported on some solid substance
ipplies just as well to a plane supported by air reaction. This
)oint can be made clear by examining the illustrations at top
f Fig. 85. In this case a pivot is used as a point of support
nd a block is carried by a plate which is supported by the
ivot point. At A the center of gravity is directly over the
oint of support and the plate is balanced. At B, the body
as been shifted on the plate, the latter being undisturbed,
he center of gravity of the combination is now to one side
I the point of support and the plate is in unstable equiUbrium.

176 The A. B. C. of Aviation

Referring to D, instead of being supported by a solid pivot
point, the plate is supported by air and two weights are pro-
vided, one at each end. If the weights are so placed that their
centers of gravity are the same distance from the center of the
plate, the center of gravity of the combination will be at the
center of the plate. The center of pressure, due to air reaction,
will be at the same point and the plate will be in a condition
of equiUbriimi. As shown at E and F, moving the weights
will change the center of gravity in relation to the center of
pressure and cause tipping of the plates. The airplane shown
at the bottom of Fig. 85 has the center of lift or pressure
directly above the center of gravity and the machine, when in
normal flying position, is in a state of equiUbrium.

As has been previously indicated to some extent, there
is a variation in the air pressure upon a plane which cannot
be absolutely determined on account of changes in wind
movement and temperature. The air itself is never at rest.
It moves upward as it becomes heated and moves down as
it is cooled and moves sideways, depending upon configura-
tions of the earth's siuf ace which, of course, varies according
to locaUty. There is nothing by which movements or velocity
of movements of the air can be predicted or known with
certainty for even a brief period in advance. The pressure
upon a given area is never constant and, as will be apparent,
the center of pressing on an aerofoil will shift constantly and
there will be considerable variation between it and the center
of gravity.

For example, a gust of wind striking one side of an airplane
in a position of equiUbrium will produce added lift on that
side if it strikes under the wing, and added weight on the side
where its force is exerted if it strikes the upper part of the
wing. In either case the effect is the same as though the center
of gravity were shifted in relation to the center of pressure
or point of support, and the airplane will tip. This move-
ment is counteracted by altering the position of the ailerons
from a neutral position so that the one on the high side is
tilted up so the air strikes its upper surface and pushes the
hi^h wing down while that on the low side is tilted down

Why Small Control Surfaces Are So Effective 177

so the air pressure strikes its under surface and tends to lift
the low wing up.

WHY SMALL CONTROL SURFACES ARE SO BFFECTIVB

The reason why an aileron or other controlling surface of
relatively small area may give positive control is because it
is carried at the end of the wing and considerable leverage is
obtained. Referring to the diagram at Fig. 86 A, we have a
condition where lever arms are of equal length, i.e., the fulcrum
or point of support is just midway between the two 100-po»md
we^ts. The combination is therefore in a condition of
balance or equilibrium. As shown at B, if thfe point of support
is shifted so that it will be near one end of the lever it will

.^^mA^

^^-

"^w^

^- 87. The Depardussin Radi^ Monoplane of tQia, a Pioneer Form lowing
Advantages of Thorough Stieamlmiug to Secure High Speed and Compact
In Piacing of WeiglitB to Secure Easj Control.

Oct take as much weight to balance 100 pounds as it did in the
Case outlined at A , where the weights were equal. When the
'ong arm of the lever is three times the length of the short
inn, it will take but one-third of the weight to secure a balance.
rhe actual figures will vary somewhat from those used because
n the example the weight of the long arm of the lever itself
nust be taken into consideration, so that somewhat less than
>ne-third the amount of weight moxmted on the short arm
>f the lever can balance it if placed at the end of the long arm.
In an airplane we have a condition similar to that shown
it B. The center of gravity of the machine is near the heavy

■r»

The A. B. C. of Atdaiion

t»^ or front, and it will take but little weight or pressure at
t*^ end of the long arm to balance the considerably greater
r^iC^* 8.t the front of the machine. In airplane design we
i^j&reiore have two classes of planes as iUustrated at Fig. 88.
7tie short type airplane is the one adapted for quick manceuvers
(e*!*^^ the. lever arms are short and the control surfaces do

Fig. 88> The Two Types of Aiiplanes in Use at the Front, Showing the Cbuic-
teiistics of Each.

not have to move as much to produce a ^ven degree of inclinar-
tion. In the large machines a different disposition of weights,
such as produced by having a cockpit for a gunner extending
some distance in front of the Mrplane will call for a propor-
tionately long^ fuselage to obtfun the required balance. As
airplane having long lever arms cannot move as quickly as the
close coupled type.

CONTROL METHODS OF EARLT AtBPULNES

The system of plane warping which was used in the early
Wright creation by which the supporting wings were distorted
at the tips is now practictdly obsolete, and nearly all ■macluiies
of modem design have ailerons or wh^ flaps to secure lateral
control. Longitudinal stability has always depended on sur-
faces carried far enough back of the center of gravity so
that a relatively small inclination would raise or depress the
tail, or, in the case of the vertical rudder, would swing it from

Control Methods of Early Airplanes 179

ade to side. In the early days there was considerable varia-
tion in the methods of actuating the surfaces for securing a
change in direction and equihbrium. The movements required
to contrbl an airplane in its flight are usually three.

In the early Antoinette monoplane machines steering
was by the usual form of rudder bar, elevation was controlled
3y a hand wheel at the right of the pilot and the lateral balance
icas controlled by a hand wheel at the left of the pilot. In
M Bleriot, steering was by the feet while a single-lever control
regulated the elevation by being pushed forward and backward
and the wing warping by being moved from side to side.

A
^ ^

fighfarUff-:^ ^^

'*''^pmgCa„fn!l//y' fhepington^rol

B X

;

\c M

7 -

Fig. Sg. DUgiam Shoving Wii^ Warpii^ Control STStem on Eariy Wright
Airplane.

This was the forerunner of the present stick control system
which is almost universally used on the light, speedy types of
lircraft. In the pioneer Wright machine steering and plane
varping were controlled by one lever while elevation was con-
rolled by another. The pilot had both hands fully occupied,
me at each lever. In the Voisin type machines first built,
teering and elevation were controlled by a wheel, the former
y turning the wheel and the latter by pushing it and the
teering post on which it was mounted, back and forth. Ver-
ical partitions were used between the planes in an endeavor

180

The A. B. C. of Aviation

to maintain transverse stability without using either
warpmg or ailerons. This system was not successful an

Fig. 90. Control Systems Used on Early Curtiss Airplanes.

soon abandoned. In the Farman machines, steering t
right or left was obtained with the rudder bar worked 1:
feet, while a single lever was pushed back and forth fc
vation and rocked to the right or left to operate the wing

Fig. 91. The Control of Early Bleriot Monoplanes was the Same in Es

as the Stick Control Now Used.

Standard Control Systems of To-day

181

In the first Curtiss machines steering was by a hand wheel,

devation was obtained by rocking the steering post back and

forth, while the ailerons were actuated by a movable seat back

or shoulder rest actuated by the operator's body. It was

i believed that the operator would lean toward the high, side

' instinctively and by so doing would tilt the ailerons at the high

side so the wind would strike the upper surface and move the

high side down. (See Fig. 90.)

STANDARD CONTROL SYSTEMS OF TO-DAY

At the present time but two systems of control are used,
the Dep., -which is an abbreviation for Depardussin, who
invented the system,, and the simple stick control. The
former is shown at Fig. 93. It consists of a hand wheel

Balancing Control

Al+i+ude ConVrol

leffSicfeof
Machine

Rig h-h Side
of Machine
Down

Righ+and Lef+Con+rol

Vym/z/m

Tmmzmm^mm^mmm^.

STANDARD DEP TYPE
AEROPLANE CONTROL

Fig. 93. Elements of Standard Dep. Control System.

182

The A. B. C. of Aviation

mounted on a control bridge, the relation of the parts being
such that the hand wheel may be oscillated at the same time
that the control bridge is pushed back and forth as desired.
The steering on a horizontal plane is obtained by a foot bar.
It is pushed with the right foot to make a right turn and
with the left foot to make a left turn. The control bridge is
pushed forward to make the airplane go down and pulled back
toward the operator to make it go up. The balancing control
wheel is rocked toward the right side of the machine if the
right wing is up and to the left side if the right wing is down.
The method of running the control cables to. secure the proper

Aileron
moves Up or
Down

^•Pulleys

Fig. 95. How Stick Control Operates Ailerons.

movement of the various control elements when the dual Dep-
system is used is clearly outUned at Fig. 92.

The stick control system, which is shown at Fig. 94, ha^
practically the same movements a^ in the Dep. system. Alti-
tude control is secured by moving the stick forward to have
the plane go down and to pull it toward the operator to have
the plane go up. The balancing control is by rocking the
stick from side to side. Directional control on a horizontal
plane is obtained by the same type foot bar as used with the
Dep. system. The diagram at Fig. 95 shows how the cable
may be connected up to operate the aileron by means of the
stitk. With the hand wheel the cable is passed pround the
control drum or large hub just as in a motor-boat steering gear.

The Function of Balanced Control 183

THE FUNCTION OF BALANCED CONTROL

In order to secure- easier control of an airplane and lessen
he amount of force exerted by the operator, some airplane
lesigners provide projections from the main control surfaces
svhich assist the operator in keeping the member in the proper
position. The German Fokker triplane, which -*i« one of the
most recent productions of the ;eni5H>y> has these balancing
portions on all of the control surfaces. For example, to keep
an aileron pressed down against the air reaction requires con-
siderable effort on tlie part of the pilot, especially on high-speed
or large machines. The flap or projecting portion of the
lileron, which is on the other side of the pivotal point, receives
he air pressure oi its lower siuiace and this force assists the
operator in keeping the aileron pulled down. The same thing
pplies if the conditions are reversed. \ In • this case the air
►ressure strikes the upper part of the balancing flap and assists
h.e operator in keeping the aileron tilted up.

The action of the projecting^ portions of the vertical rudder
nd elevator flaps is just the same as that of the similar parts
f the aileron. (See Fig. 96.)

WHY THE AIRPLANE IS BANKED IN TURNING

Anyone who has ridden a bicycle can appreciate the
i^ciportance of proper balance, and knows that the faster the
peed the easier it is to maintain equiUbrium. When rounding
'Orners, the expert rider, by proper inclination of his body
s able to turn close and at high velocities, while others less
Expert must diminish speed and make a wide turn. It is well
ki^wn that it is practically impossible to turn a comer at
speed without incUning the body enough to overcome the
tendency to resist change of direction of motion. If we con-
sider the laws of Newton as regards motion, we shall see that
the property of inertia is that a body in motion tends to move
forever in a straight line and uniformly. Therefore, when
turning a comw, by inclination of the body one changes the
jenter of mass enough so that it falls outside of the Une of
lupport and both wheel and rider revolve for a brief period

Why the Airplane is Banked in Turning 185

around the center of gravity, until the turning is completed.
After which the rider again shifts his body, so that a Une drawn
through the center of gravity, known as the Une of direction,
coincides with the line of support, when proper balance obtains
travel on a straight Une again.

In describing curves with an airplane, practically the same
conditions obtain as when riding a bicycle, and suitable com-
pensation must be made for the tendency of the machine to
throw its inner end higher than the outer m makmg the turn.
This obviously means a loss of lateral stabiUty, and while the
rider of a bicycle can accommodate himself by shifting his
center of gravity instinctively, obviously this is not possible
with an inanimate piece of mechanism, so the airplane must
be "banked" by the lateral control or ailerons if one is to make
a turn without "skidding.'' Any attempt to turn flat, or
without banking, always results in a "sidesUp."

High motor-car speeds are not possible on a circular track
imless it is banked, and speeds greater than sixty miles per
hour are hardly possible on circuits a mile in circmnference
that have practically a flat surface. Motorcycle racing has
shown that with a properly banked track high speeds are
possible even on small circuits. One can hardly compare
the two-pomt or single-Une support machine, such as the
bicycle or motorcycle, with either a three- or four-point support
vehicle as the tricycle or automobile. In the former instance,
the rider's position has material bearmg upon the balance,
whereas in the other equiUbrimn at high speed is only obtained
by a low placing of the center of gravity and proper distribu-
tion of weight. At high velocities even on a flat circular track
the cyclist can incline his body and secure practically the same
effect as though the track were banked. Obviously this is not
possible with a motor-car, and at high speeds the machine skids
around instead of running around a corner, unless the track
is banked. The faster the speed, the higher up the bank the
car must be driven, as a greater angle of incUnation is neces-
sary to offset the tipping tendency of centrifugal force.

In considering the flying machine, one can hardly make a
consistent comparison with a motor-car, as in this instance

186

The A. B. C. of Aviation

four points of support form a base within which it is not c
cult to include the line of direction and secure stabihty, ei'e..
at high speeds and angles of banking. In the flying machine,

Fig. 97. Illustrations Showing How Control ElementB are Moved to ReEUtft'
Airplane Plight.

we have theoretically but one center of support, and it ^
somewhat difficult to secure and maintain equiUbrium, even |^
straight-Una flight. We have seen that an airplane is t

Instruments for Navigating Airplanes 187

orted in the air by the reactions which result when one or '

aore plane surfaces are moved edgewise through the atmos-

)here at a small angle of incidence, either by the appUcation of

oaechanical power or by utiUzation of the force of gravity. In

the practical creation there must be provided means for securing

both transverse equilibrium, and restoring it when disturbed,

in addition to the apparatus for guiding the machine both

vertically and horizontally." In turning, an airplane should

assume practically the same position as a motor-car upon the

bank of a track, the outer end being higher than the inner end.

In this way air pressure offsets the centrifugal force and

"skidding" is reduced to a minimum. The formula in flying

is ^'bank, rudder, rudder, bank," meaning that the control

must be actuated in the order named to avoid a "flat turn."

The lateral control is operated to tilt the airplane to the proper

bank for the ridiiis of the turn and as soon as the banking

starts the ruddei; is Operated. In coming out of the ciu^e,

the rudder fs^t]^!p[itened out before the plane is balanced

laterally. Considerable experience is needed to bank the

proper anK>imt and a skilled pilot is always known by the

maipiei! in which he makes his turns.

INSTRUMENTS FOR NAVIGATING AIRPLANES

A typical cockpit of an airplane, showing the varioufe parts
comprising the control >ystem; is shown at Fig. 98- The
various indicating instnmients which assist the pilot iji con-
trollmg the machine are shown. In this the hand wheel,
iiistead of being motinted on a control bridge, is faptened
at the top of a lever which performs the same function^. An
air pressiu^e or speed indicator shows the air speed of the
i^aehine. An altimeter, which is a form of aneroid barometer,
iJidicates the height of the machine above the ground. A
tachometer is employed to show if the engine is turning at the
proper speed. The clock indicates time and is very useful
^hen used in connection with a speed indicator in determining
distance travelled. Three pressure gauges are provided, one
^dicates the oil pressure, one the pressure of air in the air
starting system used to set the motor going and the third one

188 The A. B. C. of Aviation

. the air pressure in the fuel feed system. The switch is i
to short circuit the magnetos and interrupt ignition. Throttle
and spark levera are utilized to regulate the engine speed.
When the pilot ia to make a trip of any magnitude a compa
is provided in addition to the instruments shown.

Suggestions for the Student in Flying. — To begin wi
the rules governing the handling of a plane that can be ;
down on paper are very few, for three chief reasons: First,
that no two machines handle alike; second, that no two pilot.^
fly alike; third, that atmospheric conditions change, so ofU
These so-called atmospheric conditions are the thing?

Plate 3. Complete Outfit of Tools tor Erecting and Taking Care of Airplanes.
The Outfit Shown is Adequate Equipment for a Crew of Six: Men.

"pocket." There is no such thing as an air "pocket." The
so-called air "pocket" is merely a downward current of air
which has, as above stated, a natural tendency to take the
plane in the same general direction.

The things the student learns first are the things he should

190 The/ A. B. C. of Aviation

never forget. There are two things the student should leam
first of all; i.e.j always keep flying speed, and always keep in
mind what position you are in rdative to the wind. Without
these two things in mind you cannot properly, or safely, handle
your plane — speed, especially, being the greatest factor
which is obtained and maintained from two sources, namely,
propeller thrust and gUding. In case your primary source of
speed ceases with either a known or imknown reasdDi, the
immediate thmg to do is to nose the plane into a gUde; sufiS-
cient to maintain flying speed. Don't worry about what the
trouble is before so doing, or your troubles will pile up, and
so will the machine.

Before starting on a flight look over, your machine in a
general way to check up on the inspectipn given by the me-
chanics charged with its maintenance. Do not take anybody's
word that there is enough gasoline, oil and water; check these
points yourself. Examine principal control wires and move
rudder bar and control stick or wheel in all du-ections to make
sure the control members function as they should.

Rtm Motor Slowly to Warm It. — Let motor nm idly until
it is warm and oil is circulatmg properly as indicated by oil
pressure gauge. Test engine for revolutions per minute as
indicated on the tachometer, but never race the engine for
more than a few seconds in determining this. B6«:^i!ure the
wheels are chocked or blocked or that the wings are held by
several men to prevent forward motion of the machine when
the engine is speeded up. Never run an airplane engine
unnecessarily when on the ground, as this reduces the flying
time or the service the engine will give in the air. Special
attention should be given to the way high compression engines
are run on the ground. These should never be nm at full
throttle on account of danger of preignition ; in fact, any
excessive running of such engines will result in their quick
deterioration.

As soon as you feel sure that the power-plant is fimctioning
properly and that your controls are in good condition, you
should taxi to a smooth level spot, with hard, dry ground or
short grass that will provide a. runway of several himdred

How to Attain Altitude and Handle Machine 191

yaids in the direction the wind is blowing. Avoid soft or
sandy ground or spaces having hummocks or long grass. If
in doubt about the nature of the ground have an assistant at
each lower wing tip. Watch carefully for the direction of the
wind and start off with the full power directly into the wind.
The tendency of the machine to turn to the left due to the
propeller blast striking the left side of the fin more than the
right side is counteracted by right rudder.

How to Take Off. — ^When the machine has attained fair
speed, which it will do at about 30 or 40 ft., the tail should be
raised by tilting the elevator flaps down by pushing the stick
or control bridge forward sUghtly. This keeps the machine
from leaving the ground until it reaches its proper flying speed.
When this point is reached, which varies with the construction
of the plane and velocity of the wind it is heading into, usually
at speeds of 50 to 60 miles per hour, then move the control
lever by pulling it back slowly, taking care that ailerons are in
neutral position until the machine is well lip in the air.

Take off at high speed is always best as the plane has ^

attained a certain momentum that insures a safe landing if

the power should fail suddenly. For the same reason, the

take off should be at a good climbing angle ; a machine should

never be "zoomed" or made to jump into the air by a too

rapid movement of the elevator flaps. If a machine is made

to climb at an abrupt angle, the plane is apt to stall and

sidesUp • to the ground. Zooming close to the groimd is

particularly dangerous if an engine is not developing full

power or if it should fail suddenly. StalUng is a part of

acrobatic flying and is not dangerous if carried on by a capable

pilot at sufficient height from the ground. Remember that

engine failure close to the ground always results in a crash

if it occurs when taking off too slowly or at a sharp angle.

How to Attain Altitude and Handle Machine. — As soon as
the plane is under way it should be driven in a straight line
and at a gradual angle of climb until a safe altitude is reached,
which should be between 800 and 1000 ft. It is stated that a
high-speed low angle cUmb is much better than a slower large
angle climb. The angle of climb, of course, depends on the

192 The A. B. C. of Amotion

power available and resistance of the airplane parts. A high-
powered machine of Uttle resistance can climb at angles
greatly in excess of those possible with the usual training
type of airplane.

A height of at least 1000 ft. should be attained before a
turn should be attempted by any but the most experienced
pilots. A point to bear in mind at all times is the possibiUty
of the airplane power-plant stopping, so the pilot must keep
a safe landing place within gUding distance at all times. If
one is cUmbing and it is desired to make a rather short turn,
the machine is nosed over until it is flying level in order to
keep the speed high. Simultaneously, the vertical rudder
and ailerons are operated so the turn is made in the desired
direction and banking proportional to the speed and radius
of the turn. A turn of wide radius with a minimum of bank is
better for the novice than turns of short radius which require
steep banking. If a short tiu-n is attempted and banking is
not properly done, the machine may 'skid if the banjt is not
suflScient and sidesUp if the bank is excessive and speed too
" slow. Either of these extremes is very dangerous, especially
if it occiu's close to the ground. A high angle of climb
should be avoided on account of danger from stalling, which
can only take place with safety at considerable distance
from the ground. It is said that the modem akplane of good
design has considerable inherent stabiUty and it is better to
be easy with the controls than to work them too quickly.
Owing to the spread of an airplane inamediate response >to
controls is not always obtained, a brief interval is required
to have the plane answer. The slower and larger the airplane
is, the more time is needed for controUing it. High speed,
single-seater scouts are very responsive to controls, while
bombing planes are not so manoeuverable. The controls
should not be jerked, but should be firmly and smoothly
handled. An expert pilot soon learns the feel of his ship
and operates controls smoothly while the novice cominionly
overcontrols through sudden movements continued too long.
When a safe altitude is reached the pilot need have no
• ty if a landing field is within gliding distance. The

Precautions When Landing 193

gliding possibiUties of a machine depend on its design primarily;
most machines have a gliding angle of 7 or 8 to 1, which means
that the plane will glide a distance 7 to 8 times its vertical
height. The direction of the wind has niuch to do with gUding
distance and speed. Natm-ally, the possible distance of gUde
without power will be less when the machine is going against
the wind than if it is with the wind.

When flying in a side wind it is necessary to fly at an angle
in order to proceed in a straight Une. This angle depends on
the wmd pressm-e and is necessary to effect the drift of the
machine. Drift must also be considered in making turns.
It is always best to nose down when turning in a cross wind
in order to make sure one has the proper flying speed. While
the air speed of a machine is always the same, the speed with
relation to the ground changes with the wind velocity. A
machine that would attain a speed of 70 miles per hour, rela-
tive to the ground in still air, will fly at 100 miles with a 30-
mile wind back of it and move but 40 miles relative to some
fixed point on the ground if its forward motion was opposed
by the same wind.

Precautions When Landing. — In landing, certain precau-
tions must be observed. When you feel you have approached
your landmg place suflSciently, shut off the engine, or better,
throttle it down if there is any doubt about reaching the field
on a normal gUde. Always make a landing into the wmd, as
this will exert a braking action and bring the ship to a stop
quicker. Never land in a cross wind if it can be avoided. If
It is found that the ship is too clos^ to the field to make a long,
easy gUde, a series of wide S turns can be made to reduce speed
as well as altitude. Do not attempt to spiral into a field imless
you are confident of your abiUty to execute the manoeuver
properly. If the pilot has overshot the mark to any extent,
rt is better to make a wide circle and make another try at the
field, starting your gUde at the proper distance. The long,
straight gUde into the wind is the best way for anyone to
^^e a landing, especially the novice, as it gives one a better
chance to judge both wind and distance.

Danger in Stalling. — One of the most serious mistakes the

194 The A. B. C. of Aviation

•

novice flyer is. apt to make is gliding at too flat an angle, and
the reason this is dangerous is that the loss of flying speed will
result m the plane settlmg mstead of gUding as it should.
It should be remenibered that unless flying speed is at-
tained and maintained at all tunes, that the controls
become inactive to considerable extent. The proportions of
the ailerons and elevator flaps are based at a definite air
resistance according to a speed which is but slightly less than
the normal flying speed of the machine. It is necessary to
t%a.ye a pronoimced au- pressure on all controls if they are to
fye effective, and in order to have the airplane responsive to
^l^ovements of the control planes, it is necessary to maintain
0ymg speed either by use of the motor and propeller thrusts,
^r "y ^ steep glide. In gUding, when the field is reached and
^j^e machme is 50 or 60 ft. from the ground, it is desirable to
\yeg^ ''levelUng off," but the final '4evellmg off" should not
^^ done imtil the machine has glided to a distance of ap-
j-o^dmately 6 or 7 ft. from the ground. The motor is shut
^£f and at this point the auplane is moving forward, neither
^sing nor falling imtil its flying speed stops ; thus it will sink
t,o the ground gradually as the angle of attack of the wings is
increased to bring the Uft up to the point where it will carry
the weight of the machine at a lessened speed. When the air-
plane is in the correct position for landing at its lowest flying
speed, the tail skid and wheels of the machine' should be just
grazing the ground. Always pick as smooth and level a
piece of ground as possible when making a landing, as, if the
ground is very soft or if there are hummocks or ditches, the
machine is very likely to ''nose over." This, of coiu^e, will
result in breakage of the propeller and impose considerable
strain on parts of the airplane, even if it does not result more

seriously.

Control in Making Turns.— The student aviator will per-
ceive a pronounced tendency of an airplane to "nose down"
when turning right hand and to climb when turning left hand.
The last named condition is not as noticeable as the first
named. This action is said to be due to the gyroscopic force
of the propeller and must be met by the elevators to keep the

Flying Learned Only by Practice 195

machine level. An important point to remember is that in
banks of from 20 degrees the fimctions of the rudder and
elevators really become rudders to direct the machine in a
horizontal flight, while the vertical rudder, which normally
directs its motion to the right or left, becomes an elevator to
raise the machine up and down. The pilot must bear this
in mmd and when the machine is descending at a pronounced
angle in action, all horizontal balance must be made by the
vertical rudder and not by the elevators.

Perhaps the most common cause of airplane accidents,

and one that is ever present when inexperienced pilots are

handling the machine, is what is termed as "the tail spin '' or

"spinning nose dive." The tail spin is not dangerous to an

experienced pilot if there is sufiicient altitude to correct the

machine's tendency to fall. In fact, in acrobatic flying, tail

spins are very common and are used as a method of losing

altitude. A tail spin is usually started by excessive banking

with too much rudder, and the nose end- of the machine falling,

due to stalling or engine faults. Under these circumstances

the ailerons and elevators are useless, for the air does not

strike their under surface, but their edges. The best control

Baethod.to coimteract a tail spin is to set the control lever

regulating on the ailerons and elevator in a vertical position

and to put all possible rudder on in the direction opposite to

that in which you are spinning, even though both feet must be

used on one side of the rudder bar to exert the proper pressure.

The rudder should be held in that position and the motor run

on full throttle to supply all the possible air pressura If

there is sufficient altitude the machine will gradually straighten

itself out and as soon as you realize that the rudder is function-

ing properly the same degree of control may be regained by

usmg the elevators and ailerons in order to bring the machine

to its proper flying position.

Flying Learned Only by Practice. — The point that must be
home in mind by all students of aviation is that it is not
possible to learn to fly by reading a book, any more than it is
to learn to swim or to ride a bicycle by the same method. A
certain co-operation of the senses to produce the required sense

196 The A. B. C. of Amotion

of balance is necessary and only practice under the tutelage
of a competent pilot will enable the aviator to fly. Th^e
have been exceptional cases of when men have taught them-
selves to fly, as the early experiences of the Wright brothers
and of Glen Curtiss demonstrated. At the same time, a nima-
ber of pioneers who were their contemporaries gave up theur
Uves in attempting to solve the same problems. The control
of a machine in the air is not difficult as the pilot soon learns
the necessary movements to have the plane recover its balance,
or to nose up or down. The landings are the most difficult
thing as in making functions it is only possible to make good
ones by a combination of good judgment of distance and speed
that comes naturally from considerable practice.

The following hst of precautions are pubUshed by the
Cmiiiss Aeroplane and Motor Corporation for the benefit of
pilots using their machines, and as they are easily memorized
and applied to all types they can be committed to memory
by any prospective pilot to good advantage.

IMPORTANT HINTS

1. Remember that "A stitch in time saves nine."

2. Always inspect the motor thoroughly before starting.

3. Always have plenty of oil, water and gasoline before
trying to start; all three are vital.

4. See that the radiator is full of water before starting.

5. Keep oil and gasoline clean, and free from water.

6. Oil all exposed working parts daily.

7. Be sure to retard magneto before starting; otherwise a
serious accident may result.

8. Turn on switch before trying to start.

9. Start the motor with the throttle only part way open.

10. Run the motor idle for only short periods; it is wasteful
and harmful to run idle too long.

11. Watch the lubrication constantly, it is most essential.

12. Remember that the propeller is the business end of the
motor; treat it with profound respect when it is in motion.

13. When the motor is hot allow it to idle a few minutes at
low speed before turning off the switch. This insures the

Important Hints 197

forced circulation of the cooling water until the cyUnder walls
have cooled considerably and also allows the valves to cool,
preventmg possible warping.

14. Avoid that destructive disease known a^ 'Hinkeritis";
when the motor is working satisfactorily, leave it alone.

15.* Be sure to inspect daily all bolts and nuts. Keep them
well tightened.

16. Stop the motor instantly upon detecting a knock, a
grind, or other noise foreign to perfect operation. It may
mean the difference between savmg or ruinmg the motor.

CHAPTER X

■ t

UNCRATING, SETTING UP AND ALIGNING AIRPLANE

To Unpack Curtiss Biplane — How Parts are Packed — Examination of Parts
before Assembly — ^Assembling Landing Gear to Fuselage — Panel Assembly
—Main Panels Joined to Fuselage — ^Adjustment for Dihedral — Methods of
Checking Dihedral— Checking Stagger — ^Wash-in and Wash-out— Tail
Assembly— Landing Gear — ^Horizontal Stabilizer — ^Vertical Stabilizer —
Elevators — ^Rudder — ^Aileron Adjustnlent — ^Rudder Control Adjustment —
Elevator Control Adjustment — General — Checking Alignment of Wings and
Fuselage — String and Straight Edge Method of Lining a- Jiiselage — .
Typical Airplanes in Practical Use.

While it is possible to assemble an airplane by many
methods and in various sequences, it will expedite and safeguard
many possible errors to follow closely the chronological order
established by such experience that has been gained by tho
several government schools during the past, and now adopted
as the standard by most manufacturers. The Curtiss training
biplane is taken as an example because it is a well-knowrx
pre-war type, and widely used in all parts of America and ir^
Canada:

HOW TO UNPACK A CURTISS BIPLANE

1. Fuselage. — The fuselage of the JNs comes packed irr^
special cases to prevent damage occurring while unpacking"
To assure success the following instructions should be f ollowec^
explicitly.

2. The packing case should always be kept on a flat surface
to prevent warping the body of the machine. To prevent th^
necessity of turning the fuselage over and to prevent shifting
of the motor, the case should always be kept with "Top^^
uppermost. The top may be easily recognized by its con-
struction and by the mark.

3. In opening the case use a nail puller — never an axe or
saw.

4. In taking ofif the top, draw out all the nails that are
driven through the sides and ends. This will allow the top

198

How Parts Are Packed 19J)

to be taken off whole. Pull nails from, and remove cross
braces to free propeller, which can then be lifted from case.

5. The next step is to remove the side marked "Front,"
and then the ends. All metal strips should be taken off first.
The bottom and back side are left in place.

6. The fuselage should next be lifted out, which will leave
the landing gear, wheels, etc., easily accessible,

7. The instructions for the fuselage should be followed in
removing the panels. The side marked "Top" shouki be
first removed, being careful to pull all the nails, then remove
the nails from blocks that hold the cross pieces in place.
When each set of cross pieces has been taken out the panels
may be removed from the box.

HOW PARTS ARE PACKED

The major parts of the JN4 are packed in two cases, which
may be designated by their contents as follows :

1. Fuselage.

2. Panels.

(1) The fuselage contains the motor set in place, with the
instrument board and instruments all connected up; with the
carburetor control and adjustment; throttle controls; with
Magneto cut-out switches all connected up and ready for
Operation, and with the tail skid in place. The control sticks
^re in their proper place. Around the seat-rails will be found
the leads connected to the segment of the stick control fop
operating the ailerons, while the leads for controlhng the ele-
vators will be found attached to the control walking beams,
^th ends passed through the fairleads and coiled up in the
fuselage back of the seat of the pilot. The rudder control wires
are fastened to the foot control bar, and lead to the rear end
of the fuselage cover, coiled up ready for leading through the
fuselage for fastening to the rudder.

The landing gear, with cross stay wires connected up
loosely, is completely assembled in this case. The landing
gear wheels, propeller and exhaust equipment are also in
this box. '

200 The A. B. C. of Aviation

(2) The panels with sockets and hinges all attached are
in the panel box. The transverse and longitudinal wires am
attached to the under side of the upper wing, coiled up and
ready for attaching to the lower wing. The aileron control
pulleys are in place on the under side of the upper wing; the
aileron control cables have been passed through these .pulleys
and are coiled up with shackles and pin at one end for attaching
to the control pylons of the aileron, and tumbuckles at the
other end to be attached to the lead which comes from the
stick control segment and through the side of the fuselage.
This same panel case also contains the elevators and rudder
with control pylons removed. This case contains all the
control pylons for the ailerons, elevators and rudder. In this
box 1 also are contained the panel struts and engine section
struts. The details of contents are given in the packing
Usts, marked "Panels."

When using a sling in lifting box containing the fuselage^
care should be taken that the center of the lift comes some-
what ahead of the center of the box toward the motor end-
This point can be quickly determined by trial, by lifting the
bridle imtil the box rides level.

:^;XAMINATION OF PARTS BEFORE ASSEMBLY

With each fuselage box is sent a set of assembly drawings.
These drawings shovdd be studied caxef uUy before commenctog
ereetion of machine. Each part should be identified by
'comparison with the erection prints a^ it is taken from the
box. Each part which is packed separately from the unit of
which it is a member has its identification mmaber attached-
All such units should be assembled before the machine proper
is started on. If the instructions for unpacking are followed
closely the danger of injury to members will be greatly lessened.
The entire machine has been inspected and checked before
shipment, but before setting up is attempted, go over the
machine thoroughly and note the following:

A. Fuselage.

1. That no members are bent or damaged.

Examination of Parts before Assembly 201

2. That the wires are in good condition. The fuselagfe
trussing is shipped trued up, and hard wires should
be taut. Safety wire on all tumbuckles on these
wu-es should be intact.

3. No bolts on the trussing ^ttings should be loose or
imlocked.

4. Be sure that the flexible cable leads are not kinked
or the cable worked open. These leads will be found
coiled up out of the way and should be left there
till needed.

5. Make sure that no bolts or locking devices needed
to erect the machine are missing. These bolts
have been either put in place on the fitting to which
they belong or will be foimd in a small bag in the
front part of the fuselage case.

6. See that no exposed fittings necessary for alignment
to other members are damaged or bent.

7. All motor and instrument connections should be
tight and properly made.

B. Panels and Tail Surfaces.

8. Surfaces must not be broken or torn.

9. Units should be comparatively tight and not easily
warped or bent out of alignment. This part of the
inspection is quife important, as these members are
covered and cannot be readily inspected after
erection is complete. If all members in the plane
of the trussing are in alignment and not damaged,
overstressed, or slackened, a considerable degree
of rigidity may be expected.

10. All fittings on these surfaces should be tight and all
bolts properly locked.

11. No flying, landing, or cross-bracing cables should
be kinked, or the cable strands loosened.

C. General.

12. Check off on the packing sheets the remaining
members necessary to complete the setting up.

Make siirp that all arft nrpspnt.

Make sure that all are present.

202 The A. B. C. of Aviation

Assembling Landing Gear to Fuselage. — To assemble the
landing gear, mount the wheels onto the axle and bolt in
place, the fuselage is then elevated, either by tackle or by
shims and blocking. If block and tackle are used, pass a line
under the engine bed suBports just to the rear of the radiator.
To this Une the hook of the block should be attached. Lifting
device must not be attached to any other part, as there is
danger of damaging or crushing. With the fuselage now
resting on blocking, location of same being under the fuselage,
at a vertical member of the fuselage side trussing, just ahead
of the tail skid, Uft the front end imtil the lower longeron clips
for attachment of landing gear struts clear the landing gear.
These cUps may be ' easily found on inspection. The short
bolts, with lock washers, nuts and cotters are found in the
cUps attached to the bottom longerons. With the lock
washers under the heads of the bolts, and when the clips on the
longerons line up with the clips on the ends of the landing
gear, the bolts are passed down through the holes thus aligned.
This facilitates assembling and inspection by placing the
bolts on the down side. The castellated nuts are then put on
the bolts and drawn tight until the drilled hole on the bolt
is visible through the castle of the nut. The cotter pin is then
inserted and the leaves spread back in two directions, which
locks the nut in place. When the landing gear has been
completely assembled to the fuselage, the tail of the machine
should be elevated by a horse and blocking under the tail
imtil the top longeron is level. Use a spirit level to determine
this.

The other method that may be used in raising the front
end of the fuselage to assemble the landing gear is as follows:
Take out the blocking and front flooring of the shipping case
from under the fore part of the fuselage. Insert a block imder
the bottom longerons at a point ahead of the point on which
the fuselage is resting in the case. This block should be aligned
under the vertical strut as shown in. Fig. 99. The floor to the
rear of the block may now be taken out. The nose of the
machine is elevated by lowering the tail, using the above
mentioned block as a fulcrum. The nose of the machine

Assembling Landing Gear to Fuselage 203

Properly Secured in+heCra+e

First Blocking After Removing from Croite

"t- 99- Slowing Steps in Uncratii^ Airplane Fuselage and Blocking It Up to
Take Landing Gear. A. Fuselage in Crate. 6. First Blocking. C. Blocked
Op for Landing Gear. D. Landing Gear in Place, Blocks Removed.

204 The A. B. C. of Aviation

should next be blocked up, being sure to place blocking under
radiator bracket and not under radiator. Now lift the tail
of the machine and this noee blocking will serve as a fulcrum
and the fuselage at station 4 will clear the blocking at that
point. Again block up under station 4 with wedges until
block is tight against lower longeron. Again elevate the noso
of the machine by depressing the tail. The nose blocking
will now need to be increased. Thus, by alternately changing
the fulcrum point and increasing the blocking, the nose will be

Fig. [00. Landing Gear Installed on Fuselage of Training Biplane.

finally raised to the point where the landing gear may h:>c
assembled to the fuselage. The appearance mth landing gea.f
installed is shown at Fig. 99 D and at Fig. 100.

Panel Assembly. — The engine, or center section panel,
must be erected before the main panels can be connected (o
the fuselage. The center section struts are first placed in their
sockets on the upper longerons. These posts will be found in
the panel box. The forward posts are approximately held
in place by the flexible wire lines, which will be found coiled
up and fastened to the under side of the cowl in the motor
compartment. The rear struts are approximately held in
place by the flexible wire lines leading from the lower longeron

Main Panels 206

at station 7, and will be found tied to the control stick in
the forward cockpit. The center section panel is now^^onnted
on the struts after the front transverse bracing between the
posts is trued up approximately. The engine section panel
posts and wires may then be trued up before further erection.
To obtain this condition all similar wires are adjusted to the
same length.

Main Panels. — There are two methods of assembling the
main panels to the machine. The panels, struts and wires
may be assembled before attaching to the fuselage, or assemble
the upper panel to the center section and then complete
assembly. The first method is considered the better, as it
permits of setting the main panels at the correct stagger and
dihedral, requiring less subsequent adjustment than the other
method.

First Method. All the main struts are marked with a
number. The method used is as follows : Starting with post
Uo. 1, which is the outer post on the left-hand side of the pilot
as he faces the dkection of travel, the front posts are numbered
"to No. 4, Nos. 1 and 2 being on the left side, and Nos. 3 and
-4 being on the right. The rear posts are similarly niunbered,
Irom 5 to 8, Nos. 5 and 6 being on the left and Nos. 7 and 8 on
"the right. This does not include the center section struts. (See
A, Fig. 101.)

This system of markmg also msures that the struts are not
inverted. To accomplish this, all numbers on the struts have
teen painted so that they may be read from the pilot's seat.
By this method an inverted strut can quickly be detected.

The upper left wing panel is first equipped with the front
and rear masts by inserting the masts into their sockets on the
upper surface of the panel. Then connect up the mast wires
to the anchor plates, which will be found on the upper siuf ace
of the right and left mast-socket. Use the tumbuckles to
adjust the tension of these wires, until the front and rear wing
beams become straight in a vertical plane.

Stand the upper left wing panel and the lower left wing
panel on their leading edges, properly supporting the panels
in cushioned blocks to prevent damage to the nose. Spac

206

The A. B. C. a^ Aviation

the panels apart, approxiinately equal to the length of the
struts. •

Next the diagonal cross wires must be connected up.
Connect these loosely to pennit the easy entering of the posts
into the sockets. The wires must be connected before the
posts or struts are set in place, because if the latter wk in
place the connecting of the wires to the lugs of the sockets is

.Double flyinq Cable
vV^j to Overhang ■ _,^

. Crosi Diagonal Cable
/'■ or lncia*tce Wire

^rai FrontStrv*-^ ^^k

a landing
M Cable — -

B-Copper.Tlp .^

^^ Sfruf Pin.Nut Sa^r-Wira
ond Split Pin — -^r^^^

£-ye Socki/-'' / \ ^

y^'-Relnfarctmenf Potth

ronf Slrut Fining
Lof/tr Ouferj
/

Fig. loi. Lower End of InterpUne Strut Showing Wing Fittings, andTun-
bucklea and Clevises at Fitting End of Flying and Landing Wires.

quite difficult. After these wires are thus inserted, insert the
posts and bolts into place.

Connect up loosely the landing (single) wires and flying
(double) wires of the outer bay to hold the wings together as a
unit. The outer bay is thus completely wired, though but
loosely.

The posts that are used for this left side are Nos. 1, 2, 5 and
6, according to the diagram. No. 1 is the outer front, No. 2 the
inner front, No. 5 is the outer rear, and No. 6 the inner rear.

The wings may now be erected to the fuselage. Extreme
care must be used to prevent straining or breaking them.

Main Panels

207

tPosf tPosf

—•. — I 1

tPost tPost

-^\ — f

^ FronfBeam
j^ffear Beam

Showing Numbering of Inferplane SfruH

Level --.^

,' Straight Edge

Methods of Tes+ing Dihedral

w//////////m

Wash In

How +o Compensate for Propeller Toi^que
by'Wash In and'Wash Out"

Lifting Surface ^W^M^a....... ...^

asaWina^^ V^^^^^^^^^^^^^^^^^^5??9r._ Aileron or Elevator

Aileron or Elevator
(InFlighf and as trigged )\ '

v/avaW/MW.^-W/w JS Aileron or Elevator

A/^ i-r*' c ^ c^wr (As it should be Rigged)

•Non-Lifting Surface as Stabilizer

Showing Difference in Rigging Ailerons onLI-fring
and Non-Lifffng Surfaces

'Soft Copper Wire Body' ^^'

Showing Method of Safety Wiring Turnbuckle

^Wire Loop

^*Jt**tTirottdX

Fig. 102. Diagrams Illustrating Rigging Instructions.

m^^mmm

In carrying, use boards under the wing beams so that thf
take the strain off the load. Handling the wings by using the
posts as carriers or by attachments to the leading or trailing
edges should not be attempted.

The wings must be firmly supported by slings or wooden
horses. The wings will have the appi-oximate stagger if
assembled as above, as the posts are in place and the tension
wires are adjusted to almost correct length when shipped.
Insert the hinge pins through the hinges as now coupled up.

If an overhead crane or telpherage system is at hand, tte
carrier shown at Fig. 103 can be used as shown by the dotted
installation. The lower (illustrated) condition is convenient for
hand transportation. One carrier should be inserted under
each panel point of the wings (next to the interplane posts),
care being taken to use filler or spacer blocks under the man
wing spars to carry the load and not take the weight on either
wings or fabric as this will surely injure these parts.

Adjustment for Dihedral.— The fuselage must now be
leveled up transversely and longitudinally. A spiiit level
placed across the top longerons will determine the transverse
condition. With the level placed fore-and-aft on the longerons
aft of station 5, the longitudinal level is established.

Adjust the tension on the flying and landing wires iintil
the dihedral of one (1) degree is established, also to make the
leading and trailing edges parallel and straight. The amount
of lift for the one (1) degree dihedral is 2^^ inches in 13 feet
6 inches (distance from the inner edge of the panel to the cen-
ter line outer post). An easy method for checking the correct
adjustment of the dihedral is to place a block 2^ inches high
on the upper surface of the lower wing, at the extreme inner
edge. A straight edge resting on this block and on the upper
surface of the wing (straight edge kept parallel to frojit or
rear beam) should be level. Fig. 102 B.

This may also be checked by using a light spirit level
suspended from a string or copper wire stretched over the
given range. If a block 2^i inches high be clamped to the inner
edge of the panel, and a line pulled taut from this block to
the center line of the outer beam, the level suspended next to

Adjustment for Dihedral

209

S
to

09
H

210

The A. B. C. of Aviation

the block will be sufficiently sensitive to determine the required
degree of dihedral. Fig. 102 B shows the arrangement
diagrammatically.

If the outer end of the wings is too high, the landing (single)
wires are too short and the flying (double) wires are too long.

^^^••••••••••x/i

'^•••••AV/yyyi >x ^••yyyyyxx «.

t^^..

Dihedral Board

Use of Dihedral Angle Board

I
I

^ X^fMVAW^ ^p

Use of Cords for Measuring Dihedral

Fig. 104. Use of Dihedral Board Shown at A. Checkiag Dihedral by Measure^

ments Shown at B.

Hence, loosening up equally on the inner and outer front and
rear flying (double) wires will correct this condition. If the
panels are too low (dihedral not up to one degree), reversing
the above method corrects this condition.

Three Methods of Checking Dihedral. — During the ad-
justment for stagger and dihedral the rigging for supporting
the panels must be maintained in place. Do not safety wire
one side until the opposite side has been erected. The machine

Checking Stagger

211

will then be equally loaded on both sides. Go over the di-
hedral and stagger dimension to check up any possible change.
When both sides agree with the specified values, safety wire
all tumbuckles as shown at Fig. 102 E.

First Method. 1 inch vertically in every 57 mches hori-
zontally equals one degree dihedral.

Second Method. Multiply the sine .0175 for every inch
laterally equals one degree dihedral.

^^'Board

^^1* 105. How to Check* Angle of Incidence of Wings. This is Determined on
Most Planes by Location of Wing-Panel Support Fittings on Fuselage.

Third Method. Use straight edge and Starrett protractor
IS a dihedral board.

Checking Stagger. — First Method. The plumb line can be
onveniently tied to the base of the wing mast on the upper
►anel. When checking the stagger at the inner end, the string
lay be attached to any of the upper panel upper surface fittings.

Second Method. A straight edge set vertically by plumb
level) is practical field method for checking up. Both of these
lethods are shown at Fig. 103 B.

212 The A. B. C. of Amatian

Wash-in and Wash-out.— The turning of the propeller
produces a tendency to timi the whole airplane around m the
opposite dh-ection to that m which the propeller is runmng.
This tendency was Very marked in some of the earlier machines,
especially the small monoplanes. This is overcome in some
maclunes by mcreasmg the angle of incidence of the plane on
the side which would tend to tip down and in some cases to
decrease the angle of incidence on the other side. By so
doing there is slightly more Uft on one side of the machine
than on the other, which corrects the tendency to timi around
the center line of thrust. Two terms which are used in this
connection are "wash-m" and ''wash-out.'' When the angle
of incidence increases from the center to the end of the plane
it is called "wash-in," and when it decreases from the center
to the ends it is called ''wash-out." This is clearly shown
at Fig.. 102 C.

Tail Assembly. — ^The horizontal stabilizer, vertical sta-
bilizer, rudder, and elevators are assembled to form the empen-
nage. As shown at Fig. 106, the horizontal stabilizer is mounted
at the rear end of the fuselage with its lower surface resting
on the top edge of the upper longerons. A system of struts
arranged from the imder side of the stabilizer to the lower
longerons and tail post anchors the stabilizer to the fuselage in
a fore-and-aft direction. The vertical stabilizer is anchored on
the upper center line of the horizontal stabilizer by suitable
clips and tie-down cables.

The rudder is hung from the end edge of the vertical
stabilizer and tail post of the fuselage. The guy lines from the
control braces to the trailing edge are so fixed as not to inter-
fere with the elevators during any position of operation. The
upper edge of the rudder is in a continuous line with the leading
edge of the vertical stabilizer. The elevators are arranged
on the trailing edge of the horizontal stabilizer. The inner
edges of the elevators are fixed so as to permit of operation
of the rudder through an arc of at least 30 degrees each side
of the fore-and-aft center line.

Landing Gear. — ^The landing gear is of the "V" type cross-
braced construction. It is composed of two trusses, properly

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ensions o£ Curtiss JN4 T;
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214

The A. B. C. of Aviation

^H separated and croHS-braced. The lower ends of the members of

^H each side truss end in the fittings of the continuous cord shock

^H absorber bridge. The landing gear is connected to the lower

^H longerons with proper fittings. The axle is properly stream-

^H lined. The bridge is so aligned vertically as to permit an

^H upward and downward movement of the landing gear axle.

^H The shock absorbing bridge is of the style known as the eon-

^H tinuous rubber cord shock absorber.

^^k The shock absorbing unit of the bridge is a continuous
^^■Lbwlt-up rubber cord covered with fabric. This cord is firmly

Fig. 107. Rear View ot Fuselage wifli Horizontal Stabiliser Attached.

wound around the axle saddle, which passes through the steel
bridge and rests over the axle on both sides of the struts. The
bridge itself is a lightened steel member with a slotted arrange-
ment allowing the vertical movement of the axle. This guide
for controlUng the vertical movement is curved in a transverse
direction to accommodate the vertical rotation of the axle
about one wheel in case of a side landing.

Horizontal Stabilizer.^This member is assembled to the
fuselage after the upper longeron is levelled up. Each upper
longeron has one U bolt and one special bolt to fasten down the

Vertical Stabilizer

215

horizontal stabilizer. This XI bolt is just ahead of the tail
and passes under the longeron with the legs pointing upward.
These bolts extend through the stabilizer and are fastened
(With nuts. They serve to hold the leading edge of the sta-
jbilizer. Two special bolts are arranged at the tail of the
machine so that they extend through the horizontal stabilizer,
'■ '■ An each side of the vertical stabili^ser. These bolts also
lid through a small L-shaped piece on each side, which is
I 'lied to the vertical stabilizer. This fastens both stabilizers

Adjusted

to the tail of the fuselage. These two bolts are flattened on
their lower ends so that they rest against the tail post and
are held to it by one bolt running through and by two screws,
oQe on each side. AU nuts are castellated and fastened with
cotter pins. (See Fig. 107.)

Vertical Stabilizer. — Next, the vertical stabihzer is fastened
to the horizontal stabilizer with the bolts which pass through
the fore-and-aft parts of the horizontal stabihzer and with the
hard wire stay hnes running to the upper surface of the hori-
zontal stabilizer from the top of the vertical stabilizer. The

216

The A. B. C. of Ariatio,

forward bolts pass through the clip at the lower front pomt
of the vertical stabilizer. The bolts which are fastened to the
tail post of the fuselage, and engage the after end of the hori-
zontal stabilizer, also engage the lugs fastened to the bottom
edge of the vertical stabilizer at the rear. The nuts should
be drawn up tight and locked with cotter pins. To align the
vertical stabilizer hard wire lines and tumbuckles are used.
(See Fig. 108.)

Elevators. — In assembling the elevators, first put on the
control braces which will be found with all necessary bolts,

Fig. tog. Rear View of Fuselage with Vertical Rudder iil Place.

nuts, and cotters in the case with the wing panels. The
position of the base of the control brace is indicated on Fig.
123. The upper tips of these braces point to the hinge line.
Hinges and hinge pins are used to mount the elevators to the
horizontal stabilizer. Cotter pins are used to keep the hinges
in place, and are inserted through the hol^ drilled in the
bottom of the hinge pins. (See Fig. 110.)

Aileron Adjustment 217

Rudder. — ^The control pylons or braces are first attached
to the rudder. They are so placed that the upper tips point
to the hinge line, thus matching up the holes. The bolts and
nuts for fastening braces to the rudder are shipped and fast-
ened to the braces. Before mounting the rudder, see that the
vertical stabihzeris in plumb ahgnment with the tail post.
This alignment is absolutely necessary. The rudder may
now be moimted onto the tail post and vertical stabihzer by
means of hinges. The hinge pins are now inserted in the
hinges and cotter pins put in the holes at the bottom of the
pins and spread backward. (See Fig. 109.)

Aileron Adjustment. — ^Attach both ailerons (one on each
side of machine, after having mounted control braces to
ailerons) and fasten pins of hinges with the necessary cotter
pins. Temporarily support ailerons so that their traihng
edges are one inch below the trailing edges of the upper
panels. Then connect up the flexible tie-line that, passing over
the top of the upper wmgs through fairleads, is connected
at the center by a tumbuckle and, passing through pulleys
attached to the upper surface front beam, is attached (by
shackle and pin) to the upper control brace of the aileron.
This "lead" is allowed so that, when in flight, the force of the
lift, will somewhat raise both ailerons and bring their trailing
edges on a line with the trailing edges of the panels. Now lead
the end of the aileron control Une attached to sector through
the hole in each side of the fuselage (between front and rear
seats). Uncoil the connecting line which passes over the
pulley attached to the lower surface of the upper wing near
the front outer post. Attach shackle and pin end to lower
control brace of aileron, and attach turnbuckle end to loop of
aileron control lead attached to control sector in fuselage (and
which passes through side of fuselage). In making this last
attachment, the leads should be so arranged (by moving the
I stick of the controls) that the lengths projecting through the
fuselage are equal.

Rudder Control Adjustment. — ^Uncoil the lines attached to
the rudder bar, to lead out through the upper surface of the
•fearftid of the fuselage cover, and, keeping the rudder control

218

The A. B. C. of Aviaik

bar at right angles to the longitudinal axis of the machine, fasten ^
the ends to the control braces. Next take up the slack of the
lines by means of the turnbuckles, adjusting the tension equally
in each set; the rudder control bar (foot control bar) should re-
main at right angles to the longitudinal axis when the rudder
is neutral (or in a vertical plane through this fore-and-aft axis).
Elevator Control Adjustment. — Temporarily maintain the
elevators in the plane of the horizontal stabilizer (neutra

View of Fuselage with Right-Hand Elevator Flap Installed.

position). Move the stick forward until the distance between
the instrument board and the nearer surface of the tube of the
stick is nine and one-half (9}^) inches. By fixing this distance
from the instrument board or dash to the tube of the stick, a
slight lead is given to the control for the greater range for
raising the elevators. Now uncoil the wires leading from the
clips attached to the walking beams of the stick control, and
coiled up aft of the pilot's seat. Pass the wire attached to the
lower end of the beam out through the side of the fuselage,

rough the lower of the two vertical holes, aft of the pilot's
With the control stick lashed, or fastened, to the nine
and one-half (9J^^^) inch position, connect this wire to the
lower control brace of the elevator. Repeat operation for
other side of machine.

Similarly the wire attached to upper end of the walking beam
is passed through the upper hold in fuselage side, and attached
to the upper control brace of the elevator. Photograph at Fig.
Ill .shows the general arrangement of the control wires at the
rear of the fuselage. Adjust tension in these wires by means of

tumbuckles, so that all lines have the same degree of tautness.
The elevators will then be neutral for this position of the bridge.
General. — All connections having now been made, carefully
go over each shackle, pin and tumbuckle, and see that all pins
are proi>erly in place, all nuts on bolts tight, and all cotter-
pinned. Try out all controls for action and freedom of move-
fnent. See that no brace wires are slack, yet not so taut that,
when plucked, they "sing." Attach nose or drift wires leading
from nose of machine to intermediate posts, front and rear.

820 The A. B. C. of Ariation

The lower ^vire connects up with the lower front socket on the
upper surface of the lower panel; the upper wire connects up
with the upper rear socket plate on the under side of the upper
panel, after the panels are attached to fuselage, with stagger
and dihedral properly corrected.

CHECKING ALIGNMENT OF WINGS AND FUSELAGE

To align the cellule accurately with the fuselage, measure
cai'efully from rudder post A to the rear outside bolts B of

Diagram Showing How Alignment of Wings and Fuselage is Verified.

outside strut fittings; from front bolts C of outside strut
fittings to the propeller shaft D. If the parts are in correct
ahgnment, distances C-JD will be equal to each other and
distances A-B will also [be the same on both sides of the
machine. This method is clearly outhned at Fig. 112,

STRING AND STRAIGHT EDGE METHOD OF ALIGNING A FUSELAGE
HAVING STRAIGHT TOP LONGERONS

1. True up the two front struts of the landing gear by
diagonal measurement from corresponding points on the axle.

Aligning a Fuselage Having Straight Top Longerons 221

2. Square up the master struts with the top and bottom
longerons by adjusting the interior cross wires. If there is
any difference in the width of the top and bottom longerons,
make it equal on each side. Also note that the engine beds
are parallel by proper adjustment. When adjusting one set
of side wires, always loosen the cross wires in section to be
next adjusted.

3. Square the top longeron of No. 1 section on one side of
fuselage with the center line of the master strut lengthwise.
Raise or lower opposite front flying strut until longeron of same
section is parallel with tops of master struts using the cross
wires in the No. 1 section for this adjustment.

3a. To sight top longeron on one side parallel with the
longeron on other side, place a white board about three feet*
long by 12 inches wide across top longeron, just forward of mas-
ter strut fittings ; place a black straight edge across longerons
just back of master strut fittings with the white board for a
backgroimd; place a white straight edge across top longerons
just back of front flying strut fittmgs. Now sight from the
rear of the tail post, raise or lower side to be adjusted until the
top of the white straight edge coincides over its entire length
with the top of the black straight edge.

4. Square up the side of the top longeron in No. 1 section
lengthwise with the tops of the master strut fittings by adjust-
ing the bottom cross wires in the No. 1 section. Then square
up the sides of the front flying struts with the top longerons.
This completes the No. 1 section.

5a. Now stretch a string from each side of the top longeron
at the master strut fittings (held 1 inch from the side of the
longeron by a stick 28 J^ inches long laid across fuselage) to the
tan post (held same distance apart by a straight edge laid
across center of last section).

5b. Place white straight edge in front of the rear flying
strut fittmgs. Hold the string against the bottom of this white
edge and raise or lower the rear flying strut until the string is
flush with the top of longeron, at the front of flying strut, then
sight straight edges until tops coincide. (If, when the straight
edges sight parallel, the string does not check flush with the

222 The A. B. C. of Aviation

longerons at the last adjusted strut, then the strut should be
readjusted before proeeedmg further.) This makes the top
longerons parallel in No. 2 section.

5c. Square the sides of the rear flying struts with the top
longerons, equaUzing the difference, if any, usmg the mterior
cross wires for this adjustment.

5d. Make the sides of the top longerons straight length-
wise by adjusting the bottom cross wires of No. 2 section
until the string is the same distance from the longeron at the
rear flying strut as at both the master strut and the front
flying strut, and the No. 2 section is completed.

6. Now tighten carefully the rear cross wires of the landiug
gear until they are sufficiently taut and the same tension.

7. Repeat 5a, b, c, d, in No. 3 section, but check string
flush with tops of longerons at rear flying struts instead of
front flying struts:^ ^ .^ ,7

8a. In section Np^4 iigL9,ke longerons parallel and straight as
before and then square up the sides...

8b. With side string's equal distance from each master strut
and No. 1 strut, tie-another string on the center of the No. 1
top cross strut and the center of the string spreader (straight
edge) at tail. As the longerons taper inward from the No. 1
strut to the tail post the above string is used to get the fuselage
straight by checking with the center Unes on top cross struts.

9. After getting No. 2 top cross strut central, center string
may be loosened from the tail fastening and the remaining cross
struts may be made central by holding the string on the center
mark of each strut and adjusting to the right or left until
string coincides with center mark on No. 2 top cross strut.

10. To get the longeron straight at the tail post, place thr^
cubes (each IJ^ inches square) on top longeron at last three
sections, and adjust tail post until tops of all three cubes are
fluA with the straight edge placed on them.

11. The tail post should be square with the sides of the
fuselage and to make it so, place a large square across the tops
of the top longerons at the stabiUzer section, letting one side
of it hang parallel with the fuselage; and with a straight edge
against the upper and lower rudder hinge fittings sight across

Aligning a Fuselage Having Straight Top Longerons 223

or along the edge of the straight edge and the hanging side
of the square, adjusting wires in the last section until the tail
post comes square.

12a. Engme bed and engine section. The rear ends of

the engine bed pieces are parallel with the top longerons by

then- construction and the enth^e length of the engine bed

pieces is made to coincide with the rear ends by adjusting the

side cross wires of the engine section. First ascertain which

side of the engine bed is high, then place a straight edge on top

of the top longerons over strut forward of the master strut.

If the same side shows high, then adjust by the cross wires

in the section next to the master strut. But if the longerons

are parallel, crosswise at this point, then raise the nose by

adjusting the cross wires in the nose section until the front end

of the engine bed pieces are parallel crosswise with the rear end.

12b. Raise or lower both sides of the entire engine section

imtil engine bed pieceg are parallel lengthwise with the tops

of the longerons.

12c. Fasten strings at a set distance frotn the side of lower
longerons at the rear flying struts to the side of the lower longer-
ons at the nose of the fuselage. Now adjust the nose of the
fuselage to the right or left until the string is the same set
distance from the side of the master struts. This should align
the fuselage practically acciu-ate.

Fuselage aUgnment is very important as much depends
upon its acciu'acy. If the rear end is not true and level, the
flying qualities will be impaired because the empennage will be
twisted instead of in its correct plane. Any lack of aUgnment
will be indicated by erratic flight. Just as it takes a straight,
true arrow to hit its mark, so it takes a well aUgned fuselage to
insure true flight and ready control.

TYPICAL AIRPLANES IN PRACTICAL USE

The Curtiss JN4 Airplane was a pre-war development
and has been generally described in the aviation prints, so
its construction and detail features are so well known that the
censorship regulations that apply to airplanes of recent develop-
ment designed for miUtary purposes do not prevent a brief

)

224 The A. B. C. of Aviaticm

review of the main dimensions and features of this thoroughly
tried, safe and practical airship, which is reproduced from
the instruction book of the makers. This airplane is clearly
shown at Fig. 113 and is an excellent example of conservative
yet absolutely modem airplane design.

General Dimensions:

Wing span — ^upper plane 43 ft., 75^ in.

Wing span — lower plane 33 ft., 11 Ji in.

Depth of chord 59)^ in.

Gap between planes 60 in.

Stagger 16 in.

Length of machine, over all 27 ft., 4 in.

Height of machine, over all 9 ft., 10% in.

Normal angle of incidence of panels 2 degrees

Dihedral angle 1 degree

Sweep back Od^ree

Angle of incidence of. horizontal stabilizer . Od^ree

Areas:

Upper planes* ... , . .. . . . ,\ 167.94 sq. ft

Lower planes* 149.42 sq.ft.

Ailerons (each 17.6 sq. ft.)*^ . x : ''' ■ . .[■ 35 . 20 sq. ft.

Horizontal stabilizer :. '. . •.,.• - '^-— -i 28.70 sq.ft.

Vertical stabilizer . '. . 3.80 sq.ft.

Elevators (each 11.00 sq. ft.) 22.00 sq.ft.

Rudder 12.00 sq.ft.

Weight:

Net weight, machine empty 1430 lbs.

Gross weight, machine loaded 1920 lbs.

Useful load 490 lbs.

Fuel (21 U. S. Gals.) 130.0 lbs. •

Oil 30.0 lbs.

Pilot ' 165 . lbs.

Passenger 165 . lbs.

Total .' . 490.0 lbs.

Loading per sq. ft. supporting surface 5.45 lbs.

Loading per R. H. t 21.35 lbs.

Performance:

Speed, maximum, horizontal flight 75 miles per hr.

Speed, minimum, horizontal flight 45 miles per hr.

CUmb m 10 minutes 2000ft.

Motor:

Model OX-5, " V," four-stroke cycle, 8-cylinder, water-cooled.

Horse-power (rated at 1400 R.P.M.) 90

Weight per R. H. P 4.33 lbs.

Bore and stroke 4 in. x 5 in.

* Total supporting surface. 352.56 sq. ft.

The Sopvnth Triplane 225

The Sopwith Triplane. — The following description of one of
the first Sopwith fighting triplanes appeared in the Gennan
aviation magazine ''Flugsport'' and as its main characteristics
are so well known to the German aeronautical engineers,
there can be no objection to the present pubUcation on the
part of the censors. The illustrations at Fig. 115 show the
Dftin details very clearly.

The body with tail plane and rudder is the same as that of
ihe small Sopwith single-seater biplanes. The three wings
lave a span of 8.07 m. and a chord of 1 m. The lower and
niddle wings are attached to short wing sections on the body,
vhile the upper plane fits to a center section supported by
;truts from the body.

Both spars of the upper wing are left soUd, while those of
ihe lower and middle wmgs are of I-section. The mterplane
Jtruts, which are of spruce and of streamliae section, run from
^he upper to the lower, wmg, and the hm^r ones from the
ipper wing to the bottom longeron of thei body. In order
to give a better view, the middle wing, which is on a level
ivith the pilot's eyes, is cut away near the body.

The wing bracing is in the form of streamlme wires of H in.
liameter. The very sunply arranged landing wkes are m the
3lane of the struts, while the bracing of the body struts, as
ivell as the duplicate Uft wires, are taken fiu-ther forward.

These further particulars are worthy of note : fuel capacity
or two hoiu^s, gasoline 85 Uters, oil 23 Uters; a^ea of wings
ind flaps (square meters), upper 7.90, middle 6.96, lower 7.10,
otal 21.96; area of elevators 6 by .5, of wing flaps, 1.10, of
udder .41. Angle of incidence (degrees): upper wing, root +
, tip — .8; middle, root + 1.5, tip +1.5; lower, root + .5,
ip — .5; tail plane, variable + 2 to — 2 degrees. Loading
►er square meter, empty 22.3, fully loaded 31.4; loading per
►rake H.P., empty 4.15, fully loaded 5.85.

From the rear spar of the middle wing wires are run forward
nd rearward to the upper longeron of the body, and the lower
ring also has a wire running forward to the lower longeron of the
»ody. All the planes have wing flaps, and inspection windows
f celluloid are fitted over the pulleys for the wing flap cables.

226

The A. B. C. of Aviation

The engine is a 110 H.P. Clerget rotary, and the gasoline
is led to the engine by means of a small propeller air pump
moimted on the right-hand body strut. The net weight of

ALBATBOSIll,[ai7

Ilg. ii6. Typical Single-Seat Pitting Scouts of, French, English, and German
Deaign tliat Have Been Buiil in Large Quantities. ,

the machine was found to be 490 kg. and if the useful load
is assumed to be 200 k^., we obtain a gross weight of 690 kg.
This with an area of 21.96 sq. m. would give a lift loading of
31.4 kg. per sq. m.

WEraHTS

Body with under-carriage and accessories 123 . 5

mngs 135

Tail plane, rudder aod elevator 13

En^ne 160

Gasoline tank 15

Oil tank 8.5

Air screw 18

Engine acioesBoriea 16

Mounting 3

490

Pilot 80

Gun and ammunition 40

35 litres of petrol and 23 litres of oil 80

THE NEW YORK
PUBLIC LIBRARY

A8T0«. LEKOX
TILDEN FOUNDATIONS

Typical Airplanes in Pra^fhal

Use 227

The A. B. C. of Anaiion

Typical Airplanes in Pradical Use

The A. B. C. of Aviation

CHAPTER XI

INSPECTING AIRPLANE BEFORE FLIGHT

Inspection of Propeller — ^Power-Plant — Gasoline and Oil System — Cooling
System Parts — ^Landing Gear — Fuselage Nose — ^Wing Fittings — ^Brace
Wires — Struts — Ailerons — Rudder — Fuselage Interior — Stabilizers —
Control Wires— Tail Skid.

It is important that all parts of an airplane should be
inspected thoroughly before the machine is allowed to leave
the ground, and this inspection must be carried on periodically
while the machine is in service. The inspection should follow
a certain well-devised and logical sequence of events, and
should not be done in a haphazard manner. Unless the
inspection processes follow logically and in a regular order,
the inspectors are very hkely to omit some important part
that may result in faulty action while in flight. A series of
special illustrations which accompany this chapter have been
posed by a practical aviator, and are intended to bring out the
important points that should receive periodical inspection.

Inspection of Propeller. — ^The first point that should
receive attention is the propeller. It should be carefully
examined to determine that the blades are in good condition.
This means that. they should be clean and well poUshed, and
if provided with copper or cloth tips, these should be securely
in place. Any splinters or cracks in the blade may result
disastrously; and the propeller should be removed imless both
blades are absolutely sound. The hub-assembly and the
propeller should be inspected with a view to locating any
looseness in the propeller hub bolts, or the nuts and cotter
pins. After a propeller has been in use for a time the hub
flanges may compress the wood and the propeller be loose in
the hub. This condition is easily remedied by screwing down
the propeller hub flange retention knots until the propeller is

urely clamped. Another point that should be looked at

232

Inspecting Air-plane before Flight

233

is the method of holding the propeller to the engiDe shaft.
This may be determined by grasping the propeller firmly and
shaking it to see if there is any lost motion between the hub
and the shaft. If the hub retention nuts have not been'
properly applied some looseness is apt to develop after the
machine has been in flight. A propeller should fit the engine
shaft al^lutely tight, because any looseness will result in
injurious vibration.

Inspection of Power-Plant. — ^The power-plant is the next
point which should be thoroughly checked over, and as pre-
viously emphasized, the pilot should not accept anybody's

^x(r/|

1 ^

•a,

^^i

^^T\

li'"""'

1^1 i> ^

Fig. 117. Examiiutioa of Power-Plant Should be Thcmmgh.

Opinion that the power-plant is in good condition. He should
satisfy himself of this before the machine leaves the ground.
Tte radiator and all water connections should be checked
Over to see that there are no serious water leaks. It is also
unportant that the radiator be full of water. The oil indicator
00 the side of the crank case, in some engines, will show the
Mnount of oil there is present in the sump. The external oil

234 The A. B. C. of Aviation

lines, particularly those leading to the oil pressure gauge,
should be absolutely tight, and all piping that conveys oil must
also be examined to see that the joints are securely fastened
and that there is no opportunity for loss of lubricant. The
fuel system demands a more rigid inspection than either the
cooling or oiling systems because a gasoline leak is apt to be
the cause of fire and, of course, should be guarded against.

The points that should be inspected most carefully are the
joints in the pipe line at both fuel tank and carburetor. If a
gravity feed system is installed, the inspector should make sure
that the vent in the tank filler cap is free and clear so that it
will admit air to the tank. If a pressure feed system is fitted
it is important that the tank cap and piping conveying air
pressure be absolutely tight. The reUef check valve should
be tested to see if the pressure releases at the proper point.
Excessive pressiu'e is apt to result in excessive fuel consumption.
Of course, it is important that the tank be full of gasoline.
The hand pmnp should be tested to make sure that it is in
proper working condition. If a strainer or filtering device is
included in the fuel pipe line this should be emptied from time
to time! to clean out any water or sediment that may be trapped
therein.

The engine should be run slowly to make siu'e that it is
firing on aU cyUnders and then speeded up to be sure that it
develops good power. The clearance between the valve
operating mechanism and the stems of the intake and exhaust
valves should be checked over. All wiring must be clean and
the insulation whole. It is important that all connections be
tight. The groimding switch for cutting out the magneto
should be tested to make sure that it functions properly. The
rod or wire connection going from the hand throttle lever to
the throttle of the carburetor should be inspected as, if it
should become loose in flight, the throttle might jar closed and
seriously impair the power production of the engine. Both
magneto and carburetor should be firmly attached, the former
to the bracket of the engine base, the latter to the induction
manifold. The oil pressure should be carefully watched to
make sure that it is sufficient for the engine in question. Oil

Landing Gear Inspection 235

pressures will vary from twenty to sixty pounds, depending
upon the design and type of the engine.

When examining the power-plant, especial attention mast
be directed to the parts of the ma^eto that have to do with
the timing and distribution of the ignition current. This
means that the distance between the breaker points should
be checked to make sure that it is adequate and it is well to

Fig. ii8. Eiamining Landing Gear Bracing Wires.

remove the distributor board to examine the contact brushes
and the current distributing segments if there is any tendency
for the engine to misfire slightly.

Landing Gear Inspection. — ^While at the front end of the
airplane the next logical point to inspect will be the landing
gear. The point that should receive attention first is the
tension of the bracing wires that run from the fuselage longerons
to the landing gear strut fittings. Next, the attachment of

The A. B. C. of Ariation

the wiring to the eyebolts in the landing gear and the security
wiring on the tiirnbuckles. All the nuts and bolts on the
strut sockets should be examined to make sure that none of the
nnts have loosened up, and that all the cotter pins are in place.
Examine the wheeb to see that there are no loose or broken
spokes and that the wheels run true. See that the tires are
properly inflated and make sure that they have no weak spots
or cuts in the casing that might result in a blow-out when
landing.

The wheels should be tested to make sure that they run
freely on the axle and the lock member holding the wheel in
place on the axle should be inspected to make sure that it is
securely in place. The shock-absorber rubber should be
wound evenly and have the proper tension and should be
clean. In some types of airplanes, the oil will drip from the
engine compartment and flood over the rubber shock absorbers,
which produces the rotting effect on the cable, thereby weak-
ening it and resulting in premature depreciation. The wooden
fairing on the axle should be inspected to make sure that it is
not cracked or split and that there are no splintered pieces
projecting from it.

FuselageNoseParts. — ^While at the front end of the machine,
examine carefully the front end of the fuselage to make sure
that the radiator is properly secured to the carrier plate and
that the carrier or nose plate is properly secured to the front
end of the fuselage longerons. The engine bed and engine
retaining bolts should be examined to make sure that all parts
are held tight. The wire braces in the fuselage should be
examined with special care in the front compartment, as con-
siderable strength is imparted to the engine carrying portion
of the fuselage by these wires. They should be tight and the
turnbuckles should be well safety wired. Another point at
the fuselage nose is the anchorage of the wind drag bracing,
or the drift wires as they are called. Two of these are found on,
each side of some types of airplanes, one leading to the Ic
wing, the other to the upper wing. The soldered ends of thi
wires should be examined to see that the retention fittings
in the proper tension. Another point that demands inspectii

Wing Fittings and Struts 237

is the fastening of the motor compartment cowls and the motor
hood cover. These must be secured and all screws that hold
them to the fuselage should be in place. Special care is needed
in examining any inspection doors in the motor Compartments,
as these are apt to be left unseeurely fastened and on some
typra of machines may open up and shake around when the
machine is flying.

Wing Fittings and Struts. — The next points to examine are
the wing panels and the points of attachment to the fuselage.

ling Wing Fitting and Landing and Flying Wires.

The best method of doing this is to examine completely the
wing panels on one part of the machine before taking those
on the other side. There are four points of attacliment for
the wings on each side of the fuselage, two for the upper wing
and two for the lower. The wing fitting pins should be in place
and properly cottered and safety wired. When this point has
been checked off, the flying wires should be examined, one

238 The A. B. C. cf Aviation

after the other. On those types oi marhines where double
flying wires are used, it is imperatiTe that equal attention be
paid to each wire. The wires i^ould not only have the required
tenflkm, but diould not be so tight that the struts between the
wings are bowed. The struts should be good, clear wood and
have no knots or curly grains. After the flying wires have
be^i checked over, the landing wires which are the single
cables should be inspected. While these are not as important
as the flying wires, at the same time they should have the
proper attention and all fittings should be secured. All wires
and tmnbuckles should be cleaned and greased with graphite
and hard grease to prevent all chance of rusting. The wing
fittings at the base of all the struts should show no signs of
distortion, and any extending tongues to which bracing wiring
is attached should not' be bent in such a way that the wire
cannot exert a straight pull. The bolts going through the
sockets at the base of the struts and through the wing fittings
should be properly tightened, and the nut on each bolt should
be retained with a cotter pin. The struts should not be loose
in the wing fittmgs. This can be ascertained by hitting the
side of the strut a sharp blow with the open hand at a point "
near the fitting. Any lost motion or looseness will be made
evident by a clicking noise at the fitting. The incidence wires
should be tight, as well as the landing and flying wires. These
are the wires that go from the top of a pair to the bottom of
the other of the same pair and are clearly shown. in Fig. 101
in preceding chapter.

Inspecting Ailerons. — ^An important member of the control
system that should be inspected as part of the wing panel is
the aileron or balancing flap. This should be easily operated
and should not be distorted or bent in any way. The various
points of the hinge assembly shbuld be gone over to make sure
that the pins are not unduly worn and that they are seciuely
fastened. A few drops of oil should be applied to the hinges
periodically and if the aileron is removed ior any reason, oil
and graphite should be introduced between the hinge pin and
its bearing. The control wire connections at the control wire,
or pylon, should be checked over one by one to insure that all

Inspecting Ailerons

Fig. I30. Looking Over Top Control Horn on Aileron.

Fig. 121. Inspecting Lowei Control Horn on Aileron.

2*0 The A. B. C. of Amoiwn

devise pins are properly fitted and that the wire ends leading
to the clevis^ have secure joints. Special attention should
be paid to control wires as if these are frayed at any point
they should be replaced at once. The pulleys over which
control wires run should be inspected for cracks and should
be greased to make sure that they will be free running. All
ailerons are checked in turn. On some types of machines but
two ailerons are used, one on eacli top -wing, while on others
four are provided, one on each wing tip.

Fuselage Interior. — Before working down to the empen-
nage, or tail of the machine, the cover should be taken off of

'^^^^C-^

-1^

— !S^//i/l|///f ^^^ ^"^^

^^^

V^fe^-^^

^^_._

_^^^

Kg. laa. Etfl mining Control Wires.

the fuselage and the various wires used for bracing or control
purposes should be checked over to see that they are at the
required degrees of tautness, that none of the fittings are
cracked or broken, and that all tumbuckles are properly
safety wired throughout the fuselage. The inspection of the
fuselage is an especially important matter in event of the
machine having made a rough landing, or having been in iise
on service that required frequent "taking-offs" and landings,

Fuselage Interior

I'ig. 123. Control Pylon of Elevator Shomng Wire Control Cable and Hard
Wire Biacing.

Tig. 134. Control Horn of Rudder Showing Double Control Cable, Clevises,
and Hard Bracing Wires.

242 The A. B. C. of Aviation

as instijictions at an aviation school. A rough landing is very
apt to loosen up the brace wires in the fuselage, especially if a
tful-low landing is made and the strain is taken by the tail skid
before the wheels touch the groimd.

Stabilizers and Control Wires. — In examining the hori-
zontal stabihzer, the only points that demand special attention
are the bolts that hold it in place on the fuselage and also the
braces that extend from each side of the rudder posts to the
imder side of the stabihzer. In examining the elevators, the

Fig. laj. Testing Stabilizer Attachment to Fuselage.

hinge assembly by which they are attached to the rear end
of the horizontal stabilizer and the control horn should be
gone over carefully. The same applies to the rudder, only in
this ease the hinge assembly is attached to the rudder posX
at the rear end of the fuselage. What has been said in regard
to the bearing points and control wires of the other control
surfaces apply just as well to those of the rudder.

Just ahead of the rudder a vertical stabilizer fin is installed.
The only points about this that demand attention are the
bracing wires and the bolts and nuts by which these are fastened

Stabilizers and Control Wires 243

Hg. 127. Testing Rudder Post and Lauding Gear.

244 The A. B. C. of Aviatifm ■

to the horizontal stabilizer. While at the rear end of the ma —
chine the tail skid should be looked over with special reference
to the supporting hinge or swivel which is attached to the tall
post of the fuselage, also to make sure that the wood is not
cracked ^or splintered. The tail skids of most airplanes are
pro\'ided with a removable shoe of steel which forms a rubbing
surface when the tail skid tracks on the ground, as in flying or
"taxi-ing." As soon as this shoe show signs of wear it should
be removed and replaced with a new one, as this will save the
tail skid and is much easier to do than replacing an entire tail
skid member. Special attention should be paid to the shock
absorber rubber of the tail skid.

The wing skids at the end of each wing on a machine of
considerable spread should be looked at to make sure that
these are properly secured and not cracked. The control
system parts should be checked over periodically and operated
to make sure that all the control surfaces operate as they
should. In the Dep. control, the cable passes over a drum
having a series of grooves cut into it to form a continuous
spiral around which the control wire is wrapped. The drum
around which the wire is coiled is not always of large diametfir,
and if wire of exceptional stiffne^ is used, or one that is not
exactly the proper size, it is apt to fray, due to the sharp turn
it is forced to make, whenever the control is operated.

If the machine is provided with a stick control, special
attention should be given to the universal joints which make it
possible to move the stick forward and the control bar sideways
at the same time. Naturally, every one of the multiplicity of
connections at the control boms must be examined in con-
nection with checking over the control system. Points that
are apt to be neglected, such as where the wire runs inside the
fuselage, are those which really demand inspection oftenest.
By checking over the points emmierated carefully to ascertain
if the machine is in proper flying condition before it leaves
ground, all danger of accident when in the air is minimized.

CHAPTER XII

STANDARD AIRPLANE NOMENCLATURE

Definitions of All Terms Used in Connection with Aviation Approved by National

Advisory Committee fof Aeroniutics.

For the information of those interested in aeronautics the
foUowmg nomenclature has been prepared as a guide, with
a view to eUminatrng the dupUcation of terms, the erroneous
use of terms, and confusion of terms, and to define the principal
terms which have come into use in the development of aero-
nautics. In the preparation of this nomenclature only those
tenns have been defined which are pecuUar to this subject.
Aerofoil: A wingUke structure, flat or curved, designed to
obtain reaction upon its surface from the air through which
it moves.
Aeroplane : See Airplane.
Aileron: A movable auxihary surface used to produce a

rolling moment about the fore-and-aft axis. .
Aircraft: Any form of craft designed for the navigation of
the ah-— airplanes, balloons, dirigibles, helicopters, kites,
kite balloons, ornithopters, gUders, etc.
Airplane: A form of aircraft heavier than air which has
Wing surfaces for support in the air, with stabiUzing sur-
faces, rudders for steering, and power-plant for propulsion
through the air. This term is commonly used in a more
I'estricted sense to refer to airplanes fitted with landing
gear suited to operation from the land. If the landing gear
Is suited to operation from the water, the term '^ seaplane"
is used. (See definition.)

Pusher, — A type of airplane with the propeller in the rear

of the engine.
Tractor. — ^A type of airplane with the propeller in front
of the engine.

24.5

246 The A. B. C. of Aviatim

Air-Speed Meter: An instrument designed to measure the

speed of an aircraft with reference to the air.
Altimeter: An aneroid mounted on an aircraft to indicates

continuously its height above the surface of the earth.
Anemometer : Any instrument for measuring the velocity o f

the wind;
Angle :

Of attack or of incidence of an aerofoil. — ^The acute angl^
between the direction of the relative wind and the chore:!
of sn aerofoil; i.e., the angle between the chord of an.
aerofoil and its motion relative to the air. (This defini-
tion may be extended to any body having an axis.)
Critical. — The angle of attack at which the lift curve hsLS
its first maximum; sometimes referred to as the "burble
point." (If the ''lift ciuv^e" has more than one maxi-
mum, this refers to the first one.)
Gliding. — The angle the flight path makes with the hori-
zontal when flying in still air imder the influence of
gravity alone, i.e., without power from the engme.
Appendix: The hose at the bottom of a balloon used for
inflation. In the case of a spherical balloon it also serves
for equaUzation of pressure.
Aspect Ratio: The ratio of span to chord of an aerofoil.
Aviator: The operator or pilot of heavier-than-air craft.

This term is applied regardless of the sex of the operator.
Axes of an Aircraft: Three fixed lines of reference, usually
centroidal and mutually rectangular.

The principal longitiMinal axis in the plane of symmetry,
usually parallel to the axis of the propeller, is called the
fore-and-aft axis (or longitudinal axis); the axis perpen-
dicular to this in the plane of symmetry is called the verti-
cal axis; and the third axis, perpendicular to the other two,
is called the transverse axis (or lateral axis). In mathe-
matical discussions the first of these axes, drawn from
front to rear, is called the X axis; the second, drawn up-
ward the Z axis; and the third, forming a "left-handed"
system, the Y axis.
Balancing Flaps: See Aileron.

Standard Airplane Nomenclature 247

Balloon: A form of aircraft comprising a gas bag and a
basket. The support in the air results from the buoyancy of
the air displaced by the gas bag, the form of which is main-
tained by the pressure of a contained gas lighter than air.
Barrage. — ^A small spherical captive balloon, raised as a

protection against attacks by airplanes.
CapHve.-A balloon restrained frcT free flight by means

of a cable attaching it to the earth.
Kite. — ^An elongated form of captive balloon, fitted with
tail appendages to keep it headed into the wind, and
deriving increased lift due to its axis being inclined to
the wind.
Pilot. — ^A small spherical balloon sent up to show the

direction of the wmd.
Sounding. — ^A small spherical balloon sent aloft, without
passengers, but with registerimg meteorological instru-
ments.
►^XLOON Bed : A mooring place on the ground for a captive

balloon.
►-A^ULOON Cloth : The cloth, usually cotton, of which balloon

fabrics are made.
Walloon Fabric: The finished material, usually rubberized,

of which balloon envelopes are made.
^allggnet: a small balloon within the interior of a balloon
or dirigible for the purpose of controlUng the ascent or
descent, and for maintaining pressure on the outer envelope
so as to prevent deformation. The balloonet is kept inflated
with air at the required pressure, under the control of a
blower and valves. ,

Bank: To incline an airplane laterally — i,e., to roll it about
the fore-and-aft axis. Right bank is to incline the airplane
with the right wing down. Also used as a noun to describe
the position of an airplane when its lateral axis is inclined
to the horizontal.
Barograph : An instnmient used to record variations in baro-
metric pressure. In aeronautics the charts on which the
records are made indicate altitudes directly instead of baro-
metric pressures.

248 The A. B. C. of Aviation

Basket: The car suspended beneath a balloon, for passengers,
ballast, etc.

Biplane : A form of ahplane in which the main supporting
surface is divided into two parts, one above the other.

Body of an Airplane: The structure which contains the
power-plant, fuel, passengers, etc.

Bonnet: The appUance, having the form of a parasol, which
protects the valve of a spherical balloon against rain.

Bridle : The system of attachment of cable to a balloon, in-
cludmg Unes to the suspension band.

Bull's-eyes: Small rings of wood, metal, etc., forming part of
balloon rigging, used for connection or adjustment of ropes.

Burble Point: See Angle, critical.

Cabane: a pyramidal framework upon the wing of an air-
plane, to which stays, etc., are secured.

Camber: The convexity or rise of the curve of aCn aerofoil
from its chord, usually expressed as the ratio of the maxi-
mxim departure of the cm^e from the chord to the length
of the chord. "Top camber" refers to the top surface of
an aerofoil, and "bottom camber''' to the bottom surface;
"mean camber'' is the mean of these two.

Capacity: See Load.

The cubic contents of a balloon.

Center : Of pressure of an aerofoil. — ^The point in the plane
of the chords of an aerofoil, prolonged if necessary, through
which at any given attitude the line of action of the re-

. sultant air force passes. (This definition may be extended
to any body.)

Chord : •

Of an aerofoil section. — ^A right line tangent at the front

and rear to the under curve of an aerofoil section.
Length. — ^The length of the chord is the length of the
projection of the aerofoil section on the chord.

Clinometer: See IncUnometer.

Concentration Ring: A hoop to which are attached the

ropes suspending the basket.
Control Column : The vertical lever by means of which cer-

Standard Airplane Nomenclature

tain of the principal controls are operated, usually those for
pitching and rolling.

Controls: A general term applying to the means provided
for operating the devices used to control speed, direction of
flight, and attitude of an aircraft.

Crow's Foot: A system of diverging short ropes for distribut-
ing the pull of a single rope.

Camber-'.

iUpper Plane

■\2Deqree5
-K Angle of
' Incidence

Stagger

^5 Degrees Angle
i o-f Incidence

The Deca lag e is 3 Degrees

Fig. 128. Showing D^calage.

Decalage: The angle between the chords of the principal
and the tail planes of a monoplane. The same term may be
appUed to the corresponding angle between the du-ection of
the chord or chords of a biplane and the direction of a tail
plane. (This angle is also sometimes known as the longi-
tudinal V of the two planes.) (Fig. 128, showing Decalage.)

Dihedral in an Airplane : The angle included at the inter-
section of the imaginary surfaces containmg the chords of
the right and left wings (continued to the plane of sym-
metry if necessary). This angle is measured in a plane
perpendicular to that intersection. The measure of the

250 The A. B. C. of Amotion

dihedral is taken as 90 degrees minus one-half of this angle
as defined.

The dihedral of the upper wing may and frequently does
differ from that of the lower wing in a biplane.
Dirigible: A form of balloon, the outer envelope of which
is of elongated form, provided with a propelUng system,
car, rudders, and stabiUzmg surfaces.
Non-rigid. — ^A dirigible whose form is maintained by the
pressing of the contained gas assisted by the car-sus-
pension system.
Rigid.— A dirigible whose form is mamtained by a rigid

structure contained withm the envelope.
Semirigid. — ^A dirigible whose form is maintained by
means of a rigid keel and by gas pressure.
Diving Rudder: See Elevator.

Dope : A general term appUed to the material used in treat-
ing the cloth surface of airplane members and balloons to
increase strength, produce tautness, and act as a filler to
maintain air-tightness; it usually has a cellulose base.
Drag : The component parallel to the relative wind of the total
force on an aircraft due to the air through which it moves.
That part of the drag due to the wings is called "wing
resistance'' (formerly called "drift"); that due to the rest
of the airplane is called "parasitic resistance'' (formeriy
called "head resistance").
Drift: See Drag. Also used as synonymous with "leeway/^

q.v. . ■

Drift Meter: An instrument for the measurement of the
angular deviation of an aircraft from a set course, due to
cross wmds.
Drip Cloth : A curtain around the equator of a balloon, which

prevents rain from dripping into the basket.
Elevator: A hinged sm^ace for controlling the longitudinal
attitude of an aircraft; i.e., its rotation about the trans-
verse axis.
Empennage : See Tail.

Entering Edge : The foremost edge of an aerofoil or propeller
blade.

♦'.

>i^

Standard Airplane Nomenclature

251

Envelope : The portion of the balloon or dirigible which con-
tains the gas.
(iM Equator: The largest horizontal circle of a spherical balloon.

Enfering £dge.^

- Upper Wing Span-

,'DiskAreaof
^ Propeller

k-Ovtrfia/ig-^

< Lower Wing Span

^ Overhangs

Fig. 129. Showing Entering Edge.

S^iNs: Small fixed aerofoils attached to different parts of air-
craft, in order to promote stability; for example, tail fins, •
skid fins, etc. Fins are often adjustable. They may be
either horizontal or vertical.
Plight Path : The path of the center of gravity of an aircraft

with reference to the earth.
Float: That portion of the landing gear of an aircraft which

NOSE DIVE

6LIDE

^^mw^w//^/^^^^^^^

Fig. 130. Outlining Difference between Nose Dive and Glide.

252 The A. B. C. of Aviation

provides buoyancy when it is resting on the surface of the

water.
Fuselage : See Body.
Gap : The shortest distance between the planes of the chords

of the upper and lower wmgs of a biplane.
Gas Bag: See Envelope.
Glide : To fly without engine power.
Glider: A form of aircraft similar to an airplane, but with-
out any power-plant.

When utilized in variable winds it makes use of the soaring

principles of flight and is sometimes called a soaring machine.
Gore : One of the segments of fabric composing the envelope.
Ground Cloth : Canvas placed on the groimd to protect a

balloon.
Guide Rope: The long traiUng rope attached to a spherical

balloon or dirigible, to serve as a brake and as a variable

ballast.
Guy: A rope, chain, wire, or rod attached to an object to

guide or steady it, such as guys to wing, tail, or landing

gear.
Hangar : A shed for housing balloons or airplanes.
Helicopter : A form of aircraft whos^ support in the air is

derived from the vertical thrust of propellers.
Horn : A short arm fastened to a movable part of an airplane,

serving as a lever-arm, e.g., ailer.on-hom, rudder-horn,

elevatqr-hom.
Inclinometer : An instnmient for ineasuring the angle made

by any axis of an aircraft with the horizontal, often called

a clinometer.
Inspection Window: A small transparent window in the

envelope of a balloon or in the wing of an airplane to allow

inspection of the interior.
Kite: A form of aircraft without other propelling means

than the towUne pull, whose support is derived from the

force of the wind moving past its surface.
Landing Gear : The understructure of an aircraft designed to

carry the load when resting on or running on the surface

of the land or water.

Standard Airplane Nomenclature 253

Leading Edge: See Entering edge.

Leeway: The angular deviation from a set course over the
earth, due to cross currents of wind, also called drift; hence,
"drift meter/'
Lift: The component perpendicular to the relative wind, in
a vertical plane, of the force on an aerofoil due to the air
pressure caused by motion through the air.
jIft Bracing: See Stay.
^oad:

Bead. — The structure, power-plant, aiid essential acces-
sories of an aircraft.
Full. — ^The maximum weight which an aircraft can sup-

port in flight; the "gross weight.''
Useful. — ^The excess of the full load over the dead-weight
of the aircraft itself, i.e., over the weight of its struc-
ture, power-plant, and essential accessories. (These
last must be specified.)
iOADiNG : See Wing Loading.

iOBBS : Bags at the stem of an elongated balloon designed to
give it directional stabiUty.
iONGERON: See Longitudinal.

longitudinal: A fore-and-aft member of the framing of
an airplane body, or of the floats, usually continuous across
a number of points of support.

Ionoplane: A form of airplane whose main supporting
surface is a single wing, extending equally on each side of
the body.

looRiNG Band : The band of tape over the top of a balloon
to which are attached the mooring ropes.
Iacelle: See Body. Limited to pushers.
Tet': a rigging made of ropes and twine on spherical bal-
loons, which supports the entire load carried.
►rnithopter: A form of aircraft deriving its support and
propelling force from flappmg wings.

anel: The unit plane section of which the airplane is
made.

arachute: An apparatus made like an umbrella, used to
retard the descent of a falling body.

254 The A. B. C. of Aviation

Patch System: A system of construction in which patches
(or adhesive flaps) are used in place of the suspension band.

Permeability: The measure of the loss of gas by diffusion
through the intact balloon fabric.

Pitot Tube: A tube with an end open square to the fluid
stream, used as a detector of ah impact pressure. It is
usually associated with a coaxial tube surroimding it, having
perforations normal to the axis for indicating static pres-
sure; or there is such a tube placed near it and parallel
to it, with a closed conical end and having perforations in
its side. The velocity of the fluid can be determined from
the difference between the impact pressure and the static
pressure, as read by a suitable gauge. This instrument is
often used to determine the velocity of an aircraft through
the air.

Pontoons: See Float.

Pusher : See Airplane.

Pylon : A mast or pillar serving as a marker of a course.

Race of a Propeller: See Slip stream.

Relative Wind : The motion of the air with reference to a
moving body. Its direction and velocity, therefore, are
found by adding two vectors, one being the velocity of the
air with reference to the earth, the other being equal and
opposite to the velocity of the body with reference to the
earth.

Rip Cord : The rope running from the rip panel of a balloon
to the basket, the pulling of which causes immediate defla-
tion.

Rip Panel: A strip in the upper part of a balloon which is
torn off when immediate deflation is desired.

Rudder: A hinged or pivoted surface, usually more or less
flat or streamlined, used for the purpose of controlling the
attitude of an aircraft about its "vertical" axis, ^.e., for con-
trolling its lateral movement.
Rvdder bar. — The foot bar by means of which the rudder
is operated.

Seaplane: A particular form of airplane in which the land-
ing gear is suited to operation from the water.

Standard Airplane Nomenclature i55

Serpent: A short, heavy guide rope.

Side Slipping : Slidmg downward and inward when making a
turn; due to excessive banking. It is the opposite of skid-
ding.
Skidding: Sliding sideways away from the center of the
turn in flight. It is usually caused by insufficient banking
in a turn, and is the opposite of side sHppmg.
Skids: Long wooden or metal runners designed to prevent
nosing of a land machine when landing or to prevent drop^
ping into holes or ditches in rough ground. Generally
designed to function should the landmg gear coUapse or
fail to act.
Slip Stream or Propeller Race : The stream of air driven
aft by the propeller and with a velocity relative to the
airplane greater than that of the surrounding body of
still air.
Spread : The maximum distance laterally from tip to tip of

an airplane wing.

Stability: The quaUty of an aircraft in flight which causes

it to return to a condition of equilibrium when meeting a

disturbance (This is sometimes called "dynamical sta-

bihty.'O

Directional. — Stability with reference to the vertical axis.

Inherent. — Stability of an aircraft to the disposition and

arrangement of its fixed parts.
Lateral. — Stability with reference to the longitudinal (or

fore-and-aft) axis.
Longitudinal. — Stability with reference to the lateral (or
athwartship) axis.
Stabilizer: See Fins.

Mechanical. — ^Any automatic device designed to secure
stabiUty in flight.
5tagger: The amount of advance of the entering edge of
the upper wing of a biplane over that of the lower; it is
considered positive when the upper surface is forward.
stalling: a term describing the condition of an airplane
which from any cause has lost the relative speed necessary
for steerage way and control.

256 The A. B. C. of Aviation

Statoscope : An instniment to detect the existence of a small
rate of ascent or descent, principally used in ballooning.

Stay: A wire, rope or the like, used as a tie-piece to hold ^
parts together, or to contribute stiffness; for example, the ^rf
stays of the wing and body trussing. it

Step : A break in the form of the bottom of a float. [^r

Streamline Flow: A term in hydromechanics to describe |[)v
the condition of continuous flow of a fluid, as distinguished jj^
from eddying flow, where discontinuity takes place. fix

Streamline Shape : A shape intended to avoid eddying or i^
discontinuity and to preserve streamline flow, thus keeping I ^
resistance to progress at a minimxim. f i:

Strut: A compression member of a truss frame; for instance,
the vertical members of the wing truss of a biplane.

Sweep Back: The horizontal angle between the lateral
(athwartship) axis of an airplane and the entering edge of
the main planes.

Tail: The rear portion of an aircraft, to which are usually
attached rudders, elevators, and fins.

Tail Fins : The vertical and horizontal surfaces attached to
the tail, used for stabihzing.

Thrust Deduction: Due to the influence of the propellers,
there is a reduction of pressure imder the stem of the vessel
which appreciably reduces the total propulsive effect of
the propeller. This reduction is termed "thrust deduction."

Trailing Edge : The rearmost portion of an aerofoil.

Triplane : A form of airplane whose main supporting surfaces
are divided into three parts, superposed.

Truss : The framing by which the wing-loads are transmitted
to the body; comprises struts, stays and spars.

Velometer: See Air-Speed meter and anemometer.

Vol-Pique: See Nose Dive. (Fig. 130).

Volplane: See GUde.

Wake Gain : Due to the influence of skin friction, eddying,
etc., a vessel in moving forward produces a certain forward
movement of the fluid surrounding it. The effect of this is
to reduce the effective resistance of the hull, and this effect,
due to the forward movement of the wake, is termed the

Standard Airplane Nomenclature 257

"wake gain." In addition to this effect the forward mov-

ment of this body of fiuid reduces the actual advance of the

propeller through the surrounding medium, thereby reducing

the propeller horse-power.
Warp : To change the form of the wing by twisting it, usually

by changing the inclination of the rear spar relative to the

front spar.
Wing : The main supporting surfaces of an airplane.
Wing Loading: The weight carried per unit area of sup-

portmg surface.
Wing Rib: A fore-and-aft member of the wing structure

used to support the covering and to give the wing section

its form.
Wing Spar: An athwartship member of the wing structure

resisting tension and compression.
Yaw: To swing off the course about the vertical axis, owing

to gusts or lack of directional stability.
Angle of. — ^The temporary angular deviation of the fore-
and-aft axis from the course.

INDEX

PACT.

Ader's, and Other Machines 41

Advancing Edge Width 45

Advantage of Cambered AerofoiL 62

Advantages of Fuselage ,113

Aerial Motors Must be Light 137

Aerofoil Camber, Effect of 69

Aerofoil Experiments 54

Aerofoil Sections — Fast and Slow Planes 67

Aerofoil Sections, Resistance of 22

Aerofoil Sections — Special Work 68

Aerofoil Thickness — Lift 70

Aerofoils, Design and Construction 54

Aerofoils, Pressure Distribution on 71

AGO Tractor Biplane 95

Aileron. Function 53

Aileron Projections 183

Air-Cooled Engines 143

Air, Description of 13

Aircraft Motors Balance 136

Aircraft Motors 'Must be Most Reliable 136

Aircraft Motors Nearest to Perfection 136

Aircraft, Types of 13

Air in Motion, Cause of , 14

Air in Motion, Force of 13

Air in Motion, Kite Supported by 19

Air, Navigation of the 13

Air, Perfect Liquid 154

Airplane and Bird, Aspect Ratio of 83

Airplane and Bird Flight Compared 48

-Airplane Balance and Levfer Compared 51

-Airplane Bracing Wires 103

Airplane Capable of Flight 24

Airplane Construction, Nefw Features 42

Airplane Control Methods. 51

Airplane Design Consideraftions 114

Airplane Engine Forms 141

Airplane Engine Installation 143

Airplane Equilibrium and Control Principles 171

Airplane Fuselage Construction 109

Airplane Fuselage Forms 117

259

260 Index

PAGE

Airplane in Air, Support of i6

Airplane in Flight, Four Forces Acting on 172

Airplane in Flight, Three Axes of 171

Airplane is Best, Why 17

Airplane, Make-up of 16

Airplane Mor.t Practical 17

Airplane Moves in Three Planes 48

Airplane Operation, Principle of 17

Airplane Parts of Wood 126

Airplane Power Plants 136

Airplane Principles, Elementary 19

Airplane Propeller Construction and Action 152

Airplane, Propulsive Force of 20

Airplane Supports Weight — Proof 40

Airplane Types, Comparison of Two Accepted 93

Airplane Wing Bracing 87, 100

Airplane Wing Construction . . .* 84

Airplane Wing Form 93

Airplane Wing, Typical •. 85

Airplane Wings, Side Bracing of 102

Airplanes, American Designs 229

Airplanes Automatically Stable 97

Airplanes, Early Successful 55

Airplanes, Early Types 39

Airplanes, Foreign Designs 230

Airplanes, Three Main Types 27

Air "Pocket" 189

Air Pressure to Sustain Weight I9

Air Pressure, Variation in 17^

Air Reaction on Airplane Supports Weight 40

Air Resistance 21

Air Stream Effect on Cambered Plane 61

Aligning a Fuselage Having Straight Top Longerons 220

American Airplane Designs 229

American Seaplane Designs 228

Any Airplane Will Fly with Sufficient Power 9^

Anzani, Installation of 15^

Arrangement, Construction and Bracing of Airplane Wings 9^

Arrangement of Landing Gear 108

Ascension of Balloons, Causes of 14

Ascensional Power of Warm Air 14

Aspect Ratio 57

Aspect Ratio, High vs. Low 81

Aspect Ratio of Airplane and Bird 83

Aspect Ratio of Plane 43

Atmospheric Force, Examples of 19

Attain Altitude and Handle Machine, How to 191

Attraction of Gravity 18

Automatically Stable Airplanes 97

Index 261

PAGE

Balance of Aircraft Motors 137

Balance of Airplane and Lever Compared 51

Balanced Control, Function of 183

Balancing of Propeller 167

Balancing Principles of Plane 50

Balloon Ascensions, Causes of 14

Balloon, Desired Rapid Descent of 30

Balloon, Make Up of 15

Balloon Parts, Spherical 28

Balloon Types 14

Banking Airplane in Turning ^. . . 183

Best Aerofoil Section •. 66

Best Design of Cambered Aerofoil 61

Best Lift, Cambers for 11

Best Proportions for Plane 43

Biplane Efficiency 76

Biplane or Monoplane 76

°iplane Spacing, Corrections for 78

biplane vs. Monoplane Bracing 100

^ird and Airplane Flight Compared 48

Bird and Airplane Flight Differ 48

^ird and Plane Flight Compared 47

"ird and Plane Form Compared 44

Bird Flight Difficult to Imitate 48

Birds, Prehistoric '. . 63

Birds, Weight and Flying Power of 63

Bird's Wing Camber 71

Bird's Wings, Loading of 62

Bird Wing Forms Followed 43

Blade Pitch 156

Blade Theory 158

Blimp — Dirigible Balloon Types 36

Blimp, Its Construction 36

Blimp, Military Value 38

Blimp — Non-Rigid Type 36

Blimp, Operation in Air 38

Box Kite Development 19

Braced Biplane Wing Assembly 89

Bracing Airplane Wings, Several Methods of 102

Bracing Design of Breguet 103

Bracing Interplane 91

Bracing of Airplane Wing 100

Bracing of Martin Design 103

Bracing of Typical Wing Structure loi

Bracing Sides of Airplane Wings 102

Bracing Wings of Airplane 87

Bracing Wires on Airplanes 103

262 Index

PAGE

Breguet Bracing Design .' 103

Burble Point 58

Burble Point or Critical Angle 74

Cable Ends, Flexible 105

Cable Sizes and Strengths 105

Cambered Aerofoil, Advantages of 62

Cambered Aerofoil, Best Design 61

Cambered Aerofoils, Properties of 59

Cambsred and Flat Planes Compared 59

Cambered Plane, Air Stream Effect 61

Cambered Plane vs. Flat Plane, Diagram 60

Camber of Ribs * 84

Cambers for Maximum Lift 7^

Captive Spherical Balloons, Military Value 3^

Care of Propeller 169

Cause of Air in Motion 14

Causes of Balloon Ascensions 14

Center of Gravity and Pressure I74

Center of Gravity, How Obtained 120

Center of Gravity Shifting, Effect of I75

Center of Pressure 5^

Center of Pressure, Changes of 80

Center of Pressure, How Obtained 120

Center of Pressure, Position of 74

Changes of Center of Pressure 80

Characteristics of American Pre- War Engines 150

Coal Gas vs. Hydrogen Gas 3^

Coincidence of Centers, How Obtained 119

Comparing Airplane and Bird Flight 48

Comparison of Bird and Plane Form 44

Comparison of Cambered and Flat Planes 59

Comi>arison of Plane and Bird Flight 47

Comparison of Two Accepted Airplane Types 93

Complete Enclosure, Important 118

Conditions for Practical Motor 138

Considerations of Airplane Design 114

Constructing an Airplane, Material Necessary for 134

Construction and Bracing of Landing Gear 108

Construction of Airplane Fuselage 109

Construction of Airplane Wing 84

Construction of Blimp 36

Construction of Fuselage .: 118

Construction of Zeppelin 34

Contraction and Expansion of Gas 28

Control by Dep. System 181

Control by Instinct 50

Index 263

PAGB

Control by Sense of Equilibrium Necessary 50

C6ntrol by Stick System 182

Control in Making Turns 194

Control Methods of Airplane 51

Control Methods of Early Airplanes 178

Control of Elevator 51

Control of Free Balloons , 31

Control Principles and Airplane Equilibrium 171

Control Surfaces 48

Control Systems Standard of To-day 181

Corrections for Biplane Spacing 78

Critical Angle of Incidence . . . . : 58

Critical Angle or Burble Point 74

Curtiss Creation . 109

Curtiss Flying Boats 231

Curtiss JN4 223

Curtiss vs, Wright Design, Early no

Danger in Stalling 193

Definitions of Propeller 158

Definition of Stream Line Body 115

Definition of Work 138

Dep. Control System 181

Description of Air 13

. Design and Construction of Aerofoils 54

Design Considerations of Airplane 1 14

Designing Airplanes, Principles Observed in 114

Designing Propellers, Rule Followed in 160

Design of Fuselage Framework 113

Design of Wing Sections Vary 66

Desired Rapid Descent of Balloon 30

Details of Thimbles and Turnbuckles 104

Determining Supporting Surfaces 54

Development of Box Kite 19

Diagram-Advantages of Cambered Plane 60

Diagram of Lift and Drift Value 57

Difference in Airplanes * : 24

Dihedral Angle, Lateral 98

Dihedral Angle, Longitudinal 97

Dirigible Balloon Types — ^The Blimp 36*

Dirigible Balloon Types — The Zeppelin 34

Dirigibles, Types of 15

Disc Theory 157

Distribution of Pressure en Aerofoils 71

''Dope'* Used for Wings 86

Drawback in Lack of Speed 42

Dynamic Similarity, Principle of 54

264 Index

E PEAG

Early Airplanes 39

Early Airplanes, Control Methods of 178

Early Ideas of Plane Forms 77

Early Machines Controlled by Instinct 50

Early Successful Airplanes 55

Elarly Theory of Flight Power 42

Early Wright Starting System in

Effect of Aerofoil Camber 69

Effect of Gap 77

Effect of Shifting Center of Gravity I75

Effect of Stagger 79

Effect of Varying Lower Camber 70

Effect of Wing Loading on Aerofoil Design 65

Efficient Wing Span 81

Elementary Airplane Principles 19

Elevator Control and Use 5^

Empennage, Typical of -Modern Machine 47

End Losses 59

Engine Bed Dimensions, Standard of S. F. E 14^

Engine Forms of Airplanes 14^

Engine Installation in Airplanes I43

Engines, Air and Water Cooled I45

Engines, Pre- War, Characteristics of American Types 150

Enlarged Wing Tips 95

Equilibrium and Stability, Factors Regulating I75

Evolution of Fuselage 109

Examples of Atmospheric Force 19

Expansion and Contraction of Gas 29

Fabric "Dope" 86

Fabric for Wing Covering 85

Factors and Influencing Power Needed 138

Factors Regulating Equilibrium and Stability 175

Factors Regulating Height of Landing Gear 122

Fastening of Fabric 87

First Aircraft to Navigate 14

First Flights of, Wright Brothers 42

First Successful Heavier-than-Air Flight 41

First Successful Long Airplane Flight 41

Flexible Cable Ends 105

Flight of Airplane, First Success 41

Flight of Bird and Airplane Differ 48

Flight Power Necessary 42

Flying Boats, Curtiss Design 231

Flying Hints, Important 196

Flying in a Wind 193

Index 265

PAGB

Flying Learned Only by Practice 195

Flying Machines, Three Classes of 18

Flying Machines, Value of Nature's and Man's 64

Force of Air in Motion 13

Foreign Airplane Designs 230

Forms of Airplane Engines 141

Forms of Airplane Fuselage. , 117

Forms of Airplane Wing 93

Forms of Landing Gear 120

Forms of Planes 43, 80

Four Forces Acting on Airplane in Flight 172

F'ree Balloons, Control of 31

^ree Spherical Balloons, Military Value 31

^unction of Ailerons 53

I^uselage, Advantages of 113

I^uselage, Construction of 118

I^uselage Construction of Airplanes 109

I^uselage Evolution 109

I^uselagelForpis of Airplane .^ 117

I^uselage Framework, Design of 113

l**uselage. Ideal Shape of ( . / 117

l**uselage, Modern Type of 1 18-1 19

Puselage, Monocoque Type 117

Fuselage Ratio 117

Fuselage, Two-Seated Type of i 18

f^alvanized Non-Flexible Ends 105

Gap, Effect of 77

Gap, Practical 79

Gap, Usual Spacing of 77

Gas as Lifting Power 28

Gauging Performance of Plane 56

Geared Down Propeller Drive 168

Gnome, Installation of 4, 151

Gravity, Attraction of 18

Gravity, Overcome for Airplane Flight 18

Greatest Lift by Upper Surface 75

Greatest Lifting Effort 24

Hard Wire Loop 105

Heavier-than-Air Flight; First Success 41

Heavier-than-Air-Machines, Types of 16

Height of Landing Gear 122

Henson Airplane; Cause of Failure , 39

High Angle of Incidence 71

High vs. Low Aspect Ratio 81

266 Index

PAGE

Horizontal Equivalents 98

Horse-Power, Defined 138

Horse- Power Required 138

How Airplanes Differ 24

How Coincidence of Centers is Obtained 119

How Fabric is Fastened 87

How Propellers are Balanced. 167

How to Attain Altitude and Handle Machine 191

How to Take Off 191

Hydrogen Gas for Military Balloons 30

Hydrogen Gas, Lifting Power of 15

Hydrogen Gas vs. Coal Gas 30

Illustrations of Wind-Power 19

Imitation of Birdflight Difficult 48

Importance of Complete Enclosure 118

Importance of Streamline Plane 60

Important Hints for Flying , 196

Incidence, High Angle of 71

Incidence Wires 88

Increase Resistance with Augmenting Velocity 22

Jnfluence of Lateral Dihedral 98

Insects, Square Feet Wing Area per Pound Weight 64

Inspecting Airplane before Flight 232

Aileron Inspection 238

Airplane before Flight; Inspecting of 232

Control Wires and Stabilizers 242

Fuselage Interior 240

Landing Gear Inspection 235

Nose Parts of Fuselage 236

Power-Plant Inspection 233

Propieller Inspection 232

Stabilizers and Control Wires 242

Struts and Wing Fittings 237

Wing Fittings and Struts 237

Installation of Anzani i5^

Installation of Gnome i5^

Installing Rotary and Radial Cylinder Engines I5^

Instinctive Control 5°

Instinct to Control Early Machines 5^

Instruments for Navigating Airplanes 187

Interplane Bracing 9^

Kite Balloons Best for Observation Work 33

Kite Balloon, Method of Stabilizing 34

Kite Balloons, Military Value 34

Ind&c %m

PAGE

Kite Balloon, Parts of 33

Kite Supported by Air in Motion 19

Kress's Experiments 41

Lack of Speed a Drawback 42

Lanchester's Wing- Plan Forms 83

Landing 194

Landing Gear Construction and Bracing 108

Landing Gear Forms ,, 120

Landing Gear, Height of 122

Landing Gears, Modern Types 123

Landing Gears, Pontoon Types of 126

Landing Precautions 193

Landing Wires 89

Langley's Machine 41

Lateral Dihedral, Influence of 98

Leading Edge of Plane 71

Leading Edge Should be Curved Down 60

^'Levelling Off" 194

Lift and Drift, Meaning of 56

Lift and Drift Values, Diagram of 57

Lift-Drift Ratio, Value of 57

Lift Greatest by Upper Surface 75

Lifting Effort, Greatest ' 24

Lifting Force of Plane, Cause 61

Lifting Power of Gas 28

Lifting Power of Hydrogen Gas 15

Lift Wires 89

Lighter-than-Air Craft 28

Lilienthal's Experiments 41

Linen Wing Covering 85

Loading of Bird's Wings 62

Loads on Airplane Wing Wires 91

Longitudinal Dihedral, Planes with 97

Long Lever vs. Short Lever Airplanes 177

Loop of Hard Wire 105

Main Control Surfaces 48

Main Panels ' 205

Maintenance of Propeller 169

Make-up of Airplane 16

Make-up of Balloon. 15

Making Turns, Control in 194

Manufacturing Practice of Propellers 160

Margin of Safety of Bracing Wires 91

268 Index

PAGE

Martin Side Bracing Design ^ 103

Mass of Material to Construct an Airplane 134

Material to Construct an Airplane, Mass of 134

Mathematical Consideration of Propeller Pitch 155

Maxim's Flying Machine 40

Maximum Efficiency, Position of 73

Mean Effective Pitch 155

Mean Experimental Pitch or Zero Thrust Pitch 154

Meaning of Lift and Drift 56

Metals, Strength of 133

Metals Used in Airplanes 131

Method of Stabilizing Kite Balloons 34

Method of Sustaining Flight 22

Military Balloons, Hydrogen Gas for 30

Military Value of Blimp : . . . 38

Military Value of Captive Spherical Balloons 31

Military Value of Free Spherical Balloons 31

Military Value of Kite Balloons 34

Military Value of Zeppelin 3^

Miscellaneous Material, Strength of 133

Modern Airplanes, Three of Curious Design 95

Modern Fuselage from Shape of Fish 117

Modern Fuselage Type 1 18, 119

Modern Types of Landing Gears 125

Monocoque Fuselage Type ' 117

Monoplane or Biplane 7^

Monoplane vs. Biplane Bracing 100

Monoplane Weakness 7^

Motors for Aircraft Must be Balanced 137

Motors for Aircraft Must be Light I37

Motors for Aircraft Must be Reliable 136

Motors for Aircraft Nearest to Perfection 136

Movement df Screw 158

Multiplane, Philips 40

Navigating Airplanes, Instruments for 187

Navigation of the Air 13

Negative Lift vs. Positive Lift 7^

New Features of Airplane Construction 42

Nomenclature of Standard Airplanes 245

Non-Flexible Ends Galvanized 105

Non-Rigid Type — Blimp 36

Observation Work, Kite Balloons Best for 33

Operation of Airplane, Principle of 17

Index 269

PAGE

ion of Blimp in Air .* 38

.1 Screw Propeller 152

iarly Machines and Ader's 41

ic Resistance, Reduction of 115

f Kite Balloon 33

:age of Total Load Carried 75

Liquid Air 154

Multiplane 40

f a Screw, Definition of 153

f Blade 156

nd Bird Flight Compared 47

nd Bird Form Compared 44

balancing Principles 50

'orms ; 43, 80

'orms. Early Ideas 77

''orms. Theoretical and Actual . . . ". 82

Performance Gauged 56

Proportions, The Best 43

Airplane Moves in ,. ' 48

Aspect Ratio 43

•ections, Fast and Slow 67

Staggered 78

with Longitudinal Dihedral 97

1 Types of Landing Gears 126

1 of Center of Pressure 74

1 of Maximum Efficiency 73

; and Negative Stagger 79

i Lift vs. Negative Lift 72

STecessary for Flight 42

l^ecessary to Overcome Gravity 18

leeded. Factors Influencing 138

Plants for Airplanes 136

^.equired for Sustentation 24

il Gap 79

il Motor, Conditions for 138

il Variable Camber Wing 66

il Wing Forms 93

ions When Landing 193

)ric Birds 63

5 Distribution on Aerofoils 71

2 Distribution, Securing Uniform 82

e of Dynamic Similarity 54

e of Operation of Airplane 17

e of Screw Propeller 153

es Observed in Designing Airplanes 114

es of Balancing Plane 50

270 Index

§ PAGE

Projections on Ailerons 183

Propeller Construction and Action on Airplane 152

Propeller Definitions 158

Propeller Drive, Geared Down 168

Propeller Maintenance 169

Propeller Manufacturing Practice 160

Propeller Pitch, Definition of 153

Propeller Pitch, Mathematical Consideration of 155

Propeller, Reduction Gear Drive for . 169

Propeller Thrust in Pounds Necessary 140

Propeller Woods 160

Properties of Cambered Aerofoils ' . 59

Propulsive Force of Airplane 20

Pusher Biplane Type 9^

Rapid Descent of Balloon Desired 3®

Ratio of Fuselage n?

Reduction Gear Drive for Propeller 169

Reduction of Parasitic Resistance n5

Reserve Power Necessary to Secure Flights 42

Resistance, Minimum of 24

Resistance of Aerofoil Sections 22

Resistance of Air 21

Resistance, Reduction of Parasitic n5

Retarding Forces to Flight 18

Rib Camber 84

Rigid Type — Zeppelin 34

Rotary and Radial Cylinder Engines, Installation of I5^

Rotary Engines 143

Rotary Motor, Installation of 147

Rule Followed in Designing Propellers 160

Run Motor Slowly to Warm It . . 19°

Safety Margin of Bracing Wires 9^

Screw, Definition of i5^

Screw Movement '. I5^

Screw Propeller Action, Theories of i57

Screw Propeller, Principle of I53

Screw Working in Air i54

Seaplanes, American Designs 228

Securing Uniform Pressure Distribution 82

Sense of Equilibrium Necessary for Control 5^

Setting Up of Airplane 202

Aileron Adjustment 2l7

Assembling Landing Gear to Fuselage 202

Index 271

PAGE

Setting Up of Airplane, Checking Stagger 211

Dihedral Adjustment 208

Elevator Control Adjustment 218

Elevators 216

General Adjustment 219

Horizontal Stabilizer 214

Landing Gear 212

Landing Gear to Fuselage, Assembly of 202

Panel Assembly ; 204

Rudder 217

Rudder Control Adjustment 217

Tail Assembly 212

Three Methods of Checking Dihedral 210

Vertical Stabilizer 215

Wings and Fuselage, Checking Alignment of 220

>hape of Ideal Fuselage 117

>hort Lever vs. Long Lever Airplanes 177

>ide Bracing of Airplane Wings 102

>izes and Strength of Cables 105 '

>i2es and Strength of Wires 105

imall Control Surfaces, Why So Effective 177

»pwith Triplane 225

spherical Balloon Parts 28

spinning Nose Dive or Tail Spin 195

>tabilizing Method of Kite Balloons 34

daggered Planes 78

tagger, Effect of 79

^gger. Positive and Negative 79

tailing, Danger in 193

tailing or Zooming 191

tandard Airplanes, Nomenclature of 245

tandard Control Systems of To-day 181

tandard S. A. E. Engine Bed Dimensions 148

tarting Engine with Screw 1 55

tarting System of Early Wright iii

tick Control System 182

treamline Body, Definition of 115

treamline Plane Important '60

trength and Efficiency of Wing Sections 66

trength and Sizes of Wires 105

trength of Miscellaneous Material 133

trength of Various Metals 133

trength of Various Woods 132

trength of Wing Covering 85

tudent in Flying, Suggestions for 188

aggestions for the Student in Flying 188

apporting Surfaces Determined 54

jpport of Airplane in Air 16

jstaining Effort, Varying the Degree of 20

272 Index

PAGE

Sustaining Flight, Method of 22

Sustentation, Power Required for 24

Tail Spin or Spinning Nose Dive 195

Take Off, How to 191

Taube Wing Plan 83

The Function of Balanced Control 183

Theoretical and Actual Plane Forms 82

Theories of Screw Propeller Action 157

Theory of the Blade 158

Theory of the Disc I57

Thimbles. . 106

Thimbles and Turnbuckles, Details of .• 104

Three Axes of Airplane in Flight 171

Three Classes of Flying Machines 18

Three Modem Airplanes of Curious Design 95

Thrust in Pounds Necessary i\o'

Total Load Carried, Percentage of 75

Transverse Strength of Wooden Bars I34

Turnbuckles 106

Turnbuckles and Thimbles, Details of 104

Turning, Control in i94

Turning in the Air 19^

Two-Seated Fuselage Type 118

Types of Aircraft i3

Types of Airplanes, Three Main 27

Types of Dirigibles i5

Types of Heavier-than-Air Machines 16

Typical Airplanes in Practical Use 223

Typical Airplane Wing 85

Typical Biplane View 9^

Typical Wing Structure Bracing loi

Typical Wire Bracing Arrangements ; 107

•t

Uncrating a Curtiss JN4 19^

Examination of Parts before Assembly 19^

How Parts are Packed 19^

How to Unpack a Curtiss Biplane 19^

Uncrating, Setting-Up and Aligning Airplane 19^

Upper Surface, Greatest Lift by 75

Use of Vertical Rudder 52

Use of Wing Flaps 53

Usual Spacing of Gap 77

Index 273

' PAGE

I Lift-Drift Ratio '. 57

'f Nature's and Man's Flying Machines 64

e Camber Wing, Practical 66

on in Air-Pressure 176

J Velocities, Wind-Pressure at 23

ling Wings 87

J Lower Camber, Effect of 70

1 Lift of Plane 60

1 Rudder Use 52

■ Typical Biplane 92

\ir, Ascensional Power of 14

ig up Motor 190

1 and Wash-out 212

Cooled Engines 143

ss of Monoplane 77

and Flying- Power of Birds 63

as Measure of Mass 18

Fread Depends on Spread 122

)crew Works in Air 154

Dope " is Used for Wings 86

nail Control Surfaces are so Effective 177

le Airplane is Banked in Turning 183

le Airplane is Best 17

of Advancing Edge 43

lying 193

'ower Illustrations 19

'ressure at Various Velocities 23

Lssembly of Braced Biplane 89

(racing on Airplanes lOO

lamber of Bird 71

Construction of Airplane 84

Covering Fabric 85

Covering Strength 85

Dope" , 86

lap Use 53

brm of Airplane 93

orms, Practical Design of 93

.oading, Effect on Aerofoil Design of 65

'Ian Forms of Lanchester 83

Ian of Taube 83

Arrangement, Construction and Bracing 76

ections. Deep and Shallow 65

ections, Strength and Efficiency of 66

274 Index

PAGE

Wing Sections Vary in Design. 66

Wing Span, Efficient, t 8i

Wing Thickness — Best Camber 70

Wing Tips Enlarged 95

Wing Wires, Loads on 91

Wire Bracing, Typical Arrangements of 107

Wires for Incidence 88

Wires for Landing 88

Wires for Lift 89

Wires, Sizes and Strength of 105

Wooden Bars, Transverse Strength of 134

Woods for Airplane Parts 126

Woods for Propellers 160

Woods, Strengths of 132

Work, Definition of 138

Wright Brothers* Experiments 41

•Wright Brothers' First Flights 109

Wright Creation 42

Wright vs, Curtiss Design, Early no

Zeppelin, Dirigible Balloon Types 34

Zeppelin, Its Construction 34

Zeppelin, Military Value of 36

Zero or Thrust Pitch 154

Zooming or Stalling 191

CATALOGUE

Of Ae LATEST and BEST

PRACTICAL and MECHANICAL

BOOKS

Including Automobile and Aviation Books

Any of these boohs will be sent prepaid to any part of the world,
on receipt of price. Remit by Draft, Postal Order, Express

Order or Registered Letter

Published and For Sale By

The Norman W. Henley Publishing Co.,

2 West 45th Street, New York, U.S.A.

THE NORMAN W. HENLEY PUBLISHING CO.

INDEX

PAOE8

AirBrftkes..... 21, 24

Arithmetic 14, 25, 31

Automobile Books 3, 4, 5, 6

Automobile Charts 6, 7

Automobile lotion Systems 5

Automobile Lighting 5

Automobile Questions and Answers 4

AutcMnobile Repairing 4

Automobile Starting Systems 5

Automobile Trouble Charts 5, 6

Automobile Welding 5

Aviation 7

Aviation Chart 7

Batteries, Storage 5

Bevel Gear 19

Boiler-Room Chart 9

Brazing 7

Cams 19

Carburetion Trouble Chart 6

Change Gear 19

Charts 6, 7, 8

Coal 22

Coke 9

Combustion 22

Compressed Air 10

Concrete 10, 11, 12

Concrete for Farm Use 11

Concrete for Shop Use 11

Cosmetics 27

Cyclecars 5

Dictionary 12

Dies 12, 13

Drawing 13, 14

Drawing for Plumbers 28

Drop Forging 13

Dsmamo Building 14

Electric Bells 14

Electric Switchboards 14, 16

Electric Toy Making 16

Electric Wiring 14. 15. 16

Electricity 14. 15, 16, 17

Encyclopedia 24

E-T Air Brake 24

Every-day Engineering 34

Factory Management 17

. Ford Automobile 3

Ford Trouble Chart 6

Formulas and Recipes 29

Fuel 17

Gas Construction 18

Gas Engines 18, 19

Gas Tractor *. 33

Gearing and Cams 19

Glossary of Aviation Terms 7, 12

Heating 31, 32

Horse-Power Chart 9

Hot-Water Heating 31, 32

House Wiring 15, 17

How to Run an Automobile 3

Hydraulics 5

Ice and Refrigeration 20

Ignition Systems 6

Ignition-Trouble Chart 6

India Rubber 30

Interchangeable Manufacturing 24

Inventions 20

Knots 20

Lathe Work 20

PAGM

Link Motions. 22

Liquid Air 21

Locomotive Boilers 22

Locomotive Breakdowns 22

Locomotive Engineering 21, 22. 23. 24

Machinist Book 24, 25, 26

Magazine, Mechanical 34

Manual Training 26

Marine Engineering 26

Marine Gasoline Engines 19

Mechanical Drawing < 13, 14

Mechanical Magazine 34

Mechanical Movements 25

Metal Work 12, 13

Motorcycles 5, 6

Pateiits 20

Pattern Making 27

Perfumery 27

Perspective 13

Plumbing 28. 29

Producer Gas 19

Punches 13

Questions and Answers on Automobile 4

Questions on Heating 32

Railroad Accidents 23

Railroad Charts 9

Recipe Book 29

Refrigeration 20

Repairing Automobiles 4

Rope Work 20

Rubber 30

Rubber Stamps 30

Saw FiUng 30

Saws, Management of 30

Sheet-Metal Works 12. 13

Shop Construction _ 25

Shop Management 25

Shop Practice 25

Shop Tools 25

Sketching Paper 14

Soldering 7

Splices and Rope Work 20

Steam Engineering 30. 31

Steam Heating 31. 32

Steel 32

Storage Batteries -5

Submarine Chart 9

Switchboards 14, 16

Tapers 21

Te egraphy. Wireless 17

Te ephone 16

Thread Cutting 26

Tool Making 24

Toy Making 15

Train Rules 23

Tractive Power Chart 9

Tractor. Gas 33

Turbines 33

Vacuum Heating 32

Valve Setting 22

Ventilation 31

Watch Making 33

Waterproofing 12

Welding with Oxy-acetylene Flame 5. 33

Wireless Telegraphy 17

Wiring 14. 15

Wiring Diagrams 14

4ny of these books promptly sent prepaid to any address In

the world on receipt of price.

HOW TO REMIT— By Postal Money Order, Express Money Order,

Bank Draft or Registered Letter.

CATALOGUE OF GOOD, PRACTICAL BOOKS

AUTOMOBILES AND MOTORCYCLES

e Modem Gasoline AutomobUe — ^Its Design* Construction, and Opera-
tion, 1918 Edition. By Victor W. Pag£, M.S.A.E.

This is the most complete, practical and up-to-date treatise on gasoline automobiles and their
component parts ever published. In the new revised and enlarged 1918 edition, all phases of
automobile construction, operation and maintenance are fully and completely described, and
in language anyone can understand. Every part of all types of automobiles, from light cycle-
cars to heavy motor trucks and tractors, are described in a thorough manner, not only
the automobile, but every item of it; eqmpment, accessories, tools needed, supplies and spare
parts necessary for its upkeep, are fully discussea.

It is clearly and concisely written by an expert familiar vnth every branch of the automobile industry
and the originator of the practical system of self-education on technical subjects. It is a liberal edu-
cation in tfie automobile art, useful to all who nu^or for either business or pleasure.
Anyone reading the incomparable treatise is in touch with all imi>rovements that have been
made in motor-car construction. All latest developments, such as high speed aluminum motors
and multiple valve and sleeve-valve engines, are considered in detail. The latest ignition,
carburetor and lubrication practice is outlined. New forms of change speed gears, and final
power transmission systems, and all latest chassis improvements are shown and described.
This book is used in all leading automobile schools and is conceded to be the Standard
Treatise. The chapter on Starting and Lighting Systems has been greatly enlarged, and
many automobile engineering features that have long puzzled laymen are explained so clearly
that the imderlying principles can be understood bv anyone. This book was first published
six years ago and so much new matter has been added that it is nearly twice its original size.
The only treatise covering various forms of war automobiles and recent developments in motor-
truck ^design as well as pleasure cars. This book is not too technical for the layman nor too elementary
for the more expert. It is an incomparable work of reference for home or school. 1,000 6x9 pages,
nearly 1,000 illustrations, 12 folding plates. Cloth boimd. Price fS.OO

WHAT IS SAID OF THIS BOOK:

"It is the best book on the Automobile seen up to date." — J. H. Pile, Associate Editor iluto-

mobile Trade Journal.

"Every Automobile Owner has use for a book of this character." — The Tradesman.

"This book is superior to any treatise heretofore published on the subject." — Tfie Inventive Age.

"We know of no other volume that is so complete in all its departments, and in which the wide

field of automobile construction with its mechanical intricacies is so plainly handled, both in

the text and in the matter of illustrations." — T?^e Motorist.

" The book is very thorough, a careful examination failing to disclose any point in connection

with the automobile, its care and repair, to have been overlooked." — Iron Age.

"Mr. Pag6 has done a great work, and benefit to the Automobile Field." — ^W. C. Hasford,

Mgr. Y. M. C. A. Automobile School, Boston, Mass.

"It is just the kind of a book a motorist needs 'if he wants to understand his car." — American

Thresherman.

e Model T Ford Car, Its Construction, Operation and Repair. By Victor
W. Pag6, M.S.A.E.

This is a complete instruction book. All parts of the Ford Model T Car are described and
illustrated; the construction is fully described and operating principles made clear to everyone.
Every Ford owner needs this practical book. You don't have to guess about the construction
or where the trouble is, as it shows how to take all parts apart and how to locate and fix all
faults. The writer, Mr. Pag6, has operated a Ford car for many years and writes from actual
knowledge. Among the contents are: 1. The Ford Car: Its Parts and Their Functions.
2. The Engine and Auxiliary Groups. How the Engine Works — ^The Fuel Supply System —
The Carburetor — Making the Ignition Spark — Cooling and Lubrication. 3. Details of Chassis.
Change Speed Gear — Power Transmission — Differential Gear Action — Steering Gear — Front
Axle — Frame and Springs — Brakes. 4. How to Drive and Care for the Ford. The Control
System Explained—Starting the Motor — Driving the Car — Locating Roadside Troubles —
Tire Repairs— Oiling the Chassis — ^Winter Care of Car. 5. Systematic Location of Troubles
and Remedies. Faults in Engine — Faults in Carburetor — Ignition Troubles — Cooling and
Lubrication System Defects — Adjustment of Transmission Gear — General Chassis Repairs.
95 illustrations, 300 pages, 2 large folding plates. Price $1«00

m to Bun an AutomobUe. By Victor W. Paq£, M.S.A.E.

This treatise gives concise instructions for starting and running all makes of gasoline auto-
mobiles, how to care for them, and gives distinctive features of control. Describes every
step for shifting gears, controlling engines, etc. Among the chapters contained are: I.—
Automobile Parts and Their Functions. II. — General Starting and Driving Instructions.
III. — Typical 1917 Control Systems. IV. — Care of Automobiles. 178 pages. 72 specially
made illustrations. I^ce $1*00

4 THE NORMAN W. HENLEY PUBLISHING CO.
AutomobUe Repairing Made Easy* By Victor W. Pag£, M.SA.E.

A comprehenaive* practical exposition ci every phase of modem automobile repairiog prac-
tice. Outlines every process incidental to motor car restoration. Gives plans for ^torksbop
construction, suggestions for equipment, power needed, machinery and tools necessary to
carry on business successfully. Tells how to overhaul and repair all parts of all auto-
mobiles. Everything is ezpliuned so simpy that motorists and students can acquire a full
working knowledge of automobile repairing. This work starts with the engine, then considers
carburetion,^ i^ition, cooling and lubrication systems. The clutch, change speed gearms
and transmission system are considered in detail. Contains instructions for repairing all
tjrpes of axles, steering gears and other chassis parts. Many tables, short cuts m figuring
and rules of practice are given for the mechanic. Explains fully valve and magneto timing,
"tuning" engines, systematic location of trouble, repair of ball and roller bearings, shop kinks,
first aid to injured and a multitude of subjects of interest to all in the garage and repair business.
Tk%8 book contains 8j^cial instructions on electric starting, lighting and ignition systems, tire
repairing and rebuilding, autogenous welding, brctzing and soldering, heat treatment of steel, latest
timing practice, eight and twelve-cylinder motors, etc. 5^x8. Cloth. 1,056 pages, 1,000 illus-
trations, 11 folding plates. Price $3*C0

' WHAT IS SAID OF THIS BOOK:

" 'Automobile Repairing Made Easy' is the best book on the subject I have ever seen anc
the only book I ever saw that is of any value in a garage." — Fred JefiFrey, Martinsburg, Neb.
"I wish to thank you for sending me a copy of 'Automobile Repairing Made Easy.' I do
not think it could be excelled."— -S. W. Gisnel, Director of Instruction, Y. M. C. A., Philv
delphia. Pa.

Questions and Answers Relating: to Modern AutomobUe Construction,
Driving: and Repair. By Victor W. Pag£, M.S.A.E.

A practical self-instructor for students, mechanics and motorists, consisting of thirty-seven
lessons in the form of questions and answers, written with special reference to the require-
ments of the non-technical reader desiring easily understood, explanatory matter relating
to all branches of automobiling. The subject-matter is absolutely correct and explained in
simple language. If you can't answer all of the following questions, you need this work. The
answers to these and over 2,000 more are to be foimd in its pages. Give the name of all im-
portant parts of an automobile and describe their functions. Describe action of latest types
of kerosene carburetors. What is the difference between a "double" ignition system and a
''dual" ignition system? Name parts of an induction coil. How are valves timed? "What
is an electric motor starter and how does it work? What are advantages of worm drive gear-
. ing? Name all important types of ball and roller bearings. What is a "three-quarter" float-
ing axle? What is a two-speed axle? What is the Vulcan electric gear shift? Namethe causes
of lost power in automobiles. Describe all noises due to deranged mechanism and give causest
How can you adjust a carburetor by the color of the exhaust gases? What causes "popping"
in the carburetor? What tools and supplies are needed to equip^ a car? How do you drive
various makes of cars? What is a differential lock and where is it used? Name different
systems of wire wheel construction, etc., etc. A popular work at a popular price. SH^'^ii-
Cloth. 650 pages, 350 illustrations, 3 folding plates. Price $1.50

WHAT IS SAID OF THIS BOOK:

■"If you own a car — get this book." — The Glassworker.

**Mt. Page has the faculty of making difficult subjects plain and understandable." — Bristol
Press.

"We can name no writer better qualified to prepare a book of instruction on automobiles
than Mr. Victor W. Pag6." — Scientific American.

■"The best automobile catechism that has appeared." — Automobile Topics.

"There are few men, even with long experience, who will not find this book useful, '^reat
pains have been taken to make it accurate. Special recommendation must be given to the
illustrations, which have been made specially for the work. Such excellent books as this
greatly assist in fully understanding your automobile." — Engineering News,

The Automobillst's Pocket Companion and Expense Record. Arranged by
Victor W. Pag6, M.S.A.E.

This book is not only valuable as a convenient cost record but contains much information of value
to motorists. Includes a rondensed digest of auto laws of all States, a lubrication schedule,
hints for care of Btorace battery and care of tires, location of road troubles, anti-freezing
solutions, horse-powor tablo, driving hints and many useful tables and recipes of interest to
all motorists. Not a technical book in any sense of the word, just a collection of practical
facts in simple language for the everyday motorist. Price ..... $1.00

CATALOGUE OF GOOD, PRACTICAL BOOKS 6

Ddern Starting, Lighting and Ignition Systems. By Victor W. Faq±, M.E.

This practical volume has been written with special reference to the requirements of the non-
techmcal reader desiring easily understood, explanatory matter, relating to all types of auto-
mobile ignition, starting and lighting systems. It can be understood by anyone, even without
electrical knowledge, because elementary electrical principles are considered before any at-
tempt is made to discuss features of the various systems. These basic principles are clearly
stated and illustrated with simple diagrams. All the lecuting aystema of starting, lighting and
ignition have been described and illustrated with the co-operation of the experts employed by the
manufacturers. Wiring diagrams are shown in both technical and non-technical forms. ^ All
symbols are fully explained. It is a comprehensive review of modern starting and ignition
system practice, and includes a complete exposition of storage batterer construction, care and
rei^air. All types of starting motors, generators, magnetos, and all ignition or lighting system-
units are fully explained. Every person in the automobile business needs this volume. Among
some of the subjects treated are: I. — Elementary Electricity; Current Production; Flow;
Circuits; Measurements; Definitions; Magnetism; Battery Action; Generator Action. II. — Battery
Ignition Systems. III. — Magneto Ignition Systems. IV. — ^Elementarjj Exposition of Starting
Sjrstem Principles. V. — ^Tjrpical Starting and Lighting Systems; Practical Application; Wiring
Diagrams; Auto-lite, Bijur, Delco, Dyneto-Entz, Gray and Davis, Remy, U. S. X., Westinghouse,
Bosch-Rushmore, Genemotor, North-East, etc. VI. — -Locating and Repairing Troubles in Start-
ing and Lighting Systems. VII. — ^Auxiliary. Electric Systems; Gear-shifting by Electricity;
Warning Signals; Electric Brake; Entz-Transmission, Wagner-Saxon Circuits, Wagner-
Studebaker Circuits. b}ix7}^. Cloth. 530 pages, 297 illustrations, 3 folding plates.
Price f 1.50

tomobUe Welding With the Oxy-Acetylene Flame* By M. Keith Dunham.

This is the only complete book on the "why" and "how" of Welding with the Oxy-Acetylene
Flame, and from its pages one can gain information so that he can weld anything that comes
along.

No one can afford to be without this concise book, as it first explains the apparatus to be
used, and then covers in detail the actual welding of all automobile parts. Tne welding of
aluminum, cast iron, steel, copper, brass and malleable iron is clearly explained, as well
as the proper way to burn the carbon out of the combustion head of the motor. Among the
contents are: Chapter I. — ^Apparatus Knowledge. Chapter II. — Shop Equipment and
Initial Procedure. Chapter III.— Cast Iron. Chapter IV. — ^Aluminum. Chapter V.—
Steel. Chapter VI. — Malleable Iron, Copper, Brass, Bronse. Chapter VII. — Carbon Burn-
ing and other Uses of Oxygen and Acetylene. Chapter VIII. — ^How to Figure Cost of Weld-
ing. 167 pages, fully illustrated. Price $1*00

)rage Batteries Simpllfled. By Victor W. Pag£, M.S.A.E.

A comprehensive treatise devoted entirely to secondary batteries and their maintenance,
repair and use.

This is the most up-to-date book on this subject. Describes fully the Exide, Edison, Gould,
Willard, U. S. L. and other storage battery forms in the types best suited for automobile,
stationary and marine work. Nothing of importance has been onutted that the reader should
know about the practical operation and care of storage batteries. No details have been
slighted. The instructions for charging and care have been made as simple as possible. Brief
Synopsis of Chapters: Chapter I. — Storage Battery Development; Tjrpes of Storage Bat-
teries; Lead Plate Types; The Edison Cell. Chapter II.—- Storage Battery Construction;
Plates and Girds; Plants Plates; Faur6 Plates; Non-Lead Plates; Commercial Battery
Designs. Chapter III. — Charging Methods; Rectifiers; Converters; Rheostats; Rules
for Charging. Chapter IV. — Battery Repairs and Maintenance. Chapter V. — Industrial
Application of Storage Batteries; Glossary of Storage Battery Terms. 208 Pages. Very
Fully Illustrated. Price $1*50 net*

•torcycles, Side Cars and Cyelecars; their Construction, Management
and Repair. By Victor W. Pag6, M.S.A.E.

The only complete work published for the motorcyclist and cyclecarist. Describes fully all
leadins; types of machines, their design, construction, maintenance, operation and repair.
This treatise outlines fully the operation of two- and four-cycle power plants and all ignition,
carburetion and lubrication systems in detail. Describes all representative types of free
engine clutches, variable speea gears and power transmission systems. <G|^ves complete in-
structions for operating and repairing all types. Considers fully electric self-starting and
lighting systems, all types of spring frames and spring forks and shows leading control methods.
For those desiring technical mformation a complete series of tables and many formulae to
assist in designing are included. The work tells how to figure power needed to climb grades,
overcome air resistance and attain high speeds. It shows how to select gear ratios for various
weights and powers, how to figure braking efiiciency required, gives sizes of belts and chains
to transmit power safely, and shows how to design sprockets, belt pulleys, etc. This work
also includes complete formula) for figuring horse-power, shows how dynamometer tests are

THE NORMAN W- HENLEY PUBLISHING CO

WHAT
t shonld bE

repairer'B kit." — Ameriran Sladimith,

in north

AUTOMOBILE AND MOTORCYCLE CHARTS

Chart. Location of Gasoline Engine Troubles Made Easr~A Chart Shov-
ing Sectional Ttew of Gasoline Em^ne. Compiled by Victor W. Pag^,
M.S.A,E,

B typical faur-cyllnder eoboIuu

nf tho foiir-flycle
^automobile bhIi

be iiaed to advantage by the more expert. It ehould be on the walla of everv ptiim
rivate EarnKei automobile repair shop, rlub hoiu? or arhooK It can be carried m Uh
obile or poclEet with eaee. and ivilT insure aeamnt lose of time wbea enfiaa tioul^

offered. No details omitted.

It is prepared by ■
ley rtian aver Mm

eipt of 25 cents

hcUds all portions of the Ford pi
a qf the eoEino, fupl supply aye
"i, detsiliDE all derangei

ard or work irTcaularl
» locUion ol all ens

falo "e'li^natedThc first" me "gine trQubl"i^iSSta ill
ence to the average man's needs and ia n pcactical review of a!

aulCa. Of great

ith ease and wil
bII. Prepared n

LBily reeogmied eymptomi

saw

This chart presents the plat

f^brieai^ and'^e kind of c
tanance. Sise 24i33 iaehn

nf a tvpical

Price

SB cents

Cliart. Location of Carbureton Tronbles Made Easy. Compiled by Victor

W. PAofi, M.S.A.E.

This chart shows all parts of a typical prcasuro feed fuel supply ayatem and (pves csiiawol

Price ^■. -"", °. .'"'^. . ."". .^" . I'™ .". """/.'"f 2S cents

m system using battery and maensto eum'nt
y finding ignition troubtcA and eljmimitisft

3S cents

CATALOGUE OF GOOD, PRACTICAL BOOKS

lart. Location of Cooling: and Lubrication System Faults. Compiled by
Victor W. Pag6, M.S.A.E.

This composite diagram shows a typical automobile power plant using pump circulated
water-cooling system and the most popular lubrication methocf. Gives suggestions for cur-
ing all overheating and loss of power faults due to faulty action of the oiling or cooling group.
Siae 24x38 inches. Price . )35 CentS

lart. Motorcycle Troubles Made Easy* Compiled by Victor W. Pag^.

M.S.A.E.

A chart showing sectional view of a single-cylinder gasoline engine. This chart simplifies
location of all power-plant troubles. A single-cylinder motor is shown for simplicity. It
outlines distinctly all parts liable to give trouble and also details the derangements apt to
interfere with smooth en^e operation. This chart will prove of value to all who have to do
with the operation, repair or sale of motorcycles. No details omitted. Size 30x20 inches.

Price 25 cents

AVIATION

iation Engines, their Design, Construction, Operation and Repair. By

Lieut. Victor W. Pag6, Aviation Section, S.C.U.S.R.

A practical work containing valuable instructions for aviation students, mechanicians,
squadron engineering officers and all interested in the construction and upkeep of airplane
power plants.

The rapidly increasing interest in the study of aviation, and especially of the highly developed
internal combustion engines that make mechanical ffight possible, has created a demand for a
text-book suitable for schools and home stud;y that will clearly and concisely explain the
workings of the various aircraft en^es of foreign and domestic manufacture.
This treatise, written by a recognized authority on all of the practical aspects of internal
combustion engine construction, maintenance and repair fills the need as no other book does.
The matter is logically arranged; all descriptive matter is simply expressed and copiously
illustrated so that anyone can understand airplane engine operation and rejpair even if with-
out previous mechanical training. This work is invaluable for anyone desiring to become an
aviator or aviation mechanician.

The latest rotary types, such as the Gnome, Monosoupape, and Le Rhone, are fully explained,
as well as the recently developed Vee and radial types. The subjects of carburetion, ignition,
cooling and lubrication also are covered in a thorough manner. The chapters on repair and
maintenance are distinctive and found in no other book on this subject.
Invaluable to the student, mechanic and soldier wishing to enter the aviation service.
Not a technical book, but a practical, easily understood work of reference for all interested
in aeronautical science. 576 octavo pages. 253 specially made engravings. Price . fS.OO net

GLOSSARY OF AVIATION TERMS

rmes D' Aviation, Englisli-Freneli, Frencli-Enslisli. Compiled by Lieuts.
Victor W. Pag6, A.S., S.C.U.S.R., and Paul Montariol of the French
Flying Corps, on duty on Signal Corps Aviation School, Mineola, L. I.

A complete, well illustrated volimie intended to facilitate conversation between English-

spealdng and French aviators. A very valuable book for all who are about to leave for duty

overseas.

Approved for publication by Major W. G. Kilner, S.C., U.S.C.O. Signal Corps Aviation

School. Hazlehurst Field, Mineola, L. I.

This book should be in every Aviator's and Mechanic's Kit for ready reference. 128 pages.

Fully illustrated willi detailed engravings. Price $1*00

ation Chart. Location of Airplane Power Plant Troubles Made Easy.

By Lieut. Victor W. Pag6, A.S., S.C.U.S.R.

A large chart outlining all parts of a typical airplane power plant, showing the points where
trouble is apt to occur and suggesting remedies for the common defects. Intended espe-
cially for Aviators and Aviation Mechanics on School and Field Duty. Price . . 50 CentS

BRAZING AND SOLDERING

^ng and Soldering. By James F. Hobart.

The only book that shows you just how to handle any Job of brazing or soldering that comes
along; it tells you what mixture to use, how to make a furnace if you need one. Full of valu-
able kinks. The fifth edition of this book has just been published, and to it much new mat-
ter and a large number of tested formulae for all kinds of solders and fluxes have been added.
Illustrated. Price 25 Cent

8 THE NORMAN W. HENLEY PUBLISHING CO.

■ — ^^^^^— ■ - ^""^^ "~^^

CHARTS

AYlatlon Chart. Loeatlon of Airplane Power Plant Troubles Made Easy.

By lieut. Victor W. Pag£, A.S., S.C.U.S.R.

A large chart outlining all parts of a typical airplane power plant, showing the points where
trouble is apt to occur and suggesting remedies for the common defects. Intended especially
for Aviators and Aviation Mechanics on 8chool and field Duty. Price .... 50 €6DtS

Gasoline Engine Troubles Made Easy— A Chart Showing Sectional View of
Gasoline Eng:lne. Compiled by Lieut. Victor W. Pag£, A.S., S.C.U.S.R.

It shows clearly all parts of a typical four^ylinder gasoline engine of the four-cycle type.
It outlines distinctly all parts liable to give trouble and also 4^^^ the derangements apt
to interfere with smooth engine operation.

Valuable to students, motorists, mechanics, repairmen, garagemen, automobile salesmen,
chauffeurs, motor-boat owners, motor-truck and tractor drivers, aviators, motor-cyclists,
and all others who have to do with gasoline power plants.

It simplifies location of all engine troubles, and while it will prove invaluable to the novice,
it can be iLsed to advantage by the more expert. It should be on the walls of every public
and private garage, automobile repair shop, club house or school. It can be carried m the
automobile or pocket with ease and will insure against loss of time when engine trouble mani-
fests itself. ....

Thb sectional view of engine is a complete I'eview of all motor troubles. It is prepared by a
practical motorist for all who motor. No details omitted. Size 25x38 inches. Price 25 CentS

Lubrication of the Motor Car Chassis*

This chart presents the plan view of a typical six-cylinder chassis of standard design and
all parts are clearly indicated that demand oil, also the frequency with which they must be
lubricated and the kind of oil to use. A practical chart for all interested in motor-car main-
tenance. Size 24x38 inches. Price ^ CentS

Location of Carburetion Troubles Made Easy.

This chart shows all parts of a typical pressure feed fuel supply syBtem and gives causes of
trouble, how to locate defects and means of remedying them. Size 24x38 inches.

Price 25 cents

Location of Isnnltion System Troubles Made Easy.

In this chart all parts of a t3i)ical double ignition sj stem usin^ battery and magneto current
are shown and suggestions are given for readily tLiding igmtion troubles ana eliminating
them when found. Size 24x38 inches. Price 25 CentS

Location oi Cooling and Lubrication System Faults.

This composite chart shows a typical automobile power plant using pumi> circulated water*
cooling system and the most popular lubrication method. Gives suggestions for curing all
overheating and loss of power faults due to faulty action of the oiling or cooling group. Size
24x38 inches. Price ;^ CCntS

Motorcycle Troubles Made Easy — ^A Chart Showing Sectional View of Single-
Cylinder Gasoline Engine. Compiled by Victor W. Pag6, M.S.A.E.

This chart simplifies location of all power-plant troubles, and will prove invaluable to all
who have to do with the operation, repair or sale of motorcycles. No details omitted. Size
25x38 inches. Price 25 CCntS

Location of Ford Engine Troubles Made Easy. ompiled by Victor W.
Pag6, M.S.A.E.

This shows clear sectional views depicting all portions of the Ford power plant atid auxiliary
group>8. It outlines clearly all parts of the engine, fuel supply system, ignition group and
cooling system, that are apt to give trouble, detailing all derangements that arp liable to
make an engine lose power, start hard or work irregularly. This chart is valuable to students,
owners, and drivers, as it simplifies location of all engine faults. Of great advantage as an
instructor for the novice, it can be used equally well by the more expert as a work of reference
and review. It can be carried in the toolbox or pocket with ease and will^ save its cost in
labor eliminated the first time engine trouble manifests itself. Prepared with special refer-
ence to the average man's needs and is a practical review of all motor troubles because it is
based on the actual experience of an automobile engineer-mechanic with the mechanism the
chart describes. It enables the non-technical owner or operator of a Ford car to locate en-
gine derangements by systematic search, guided by easily recognized i»rmptoms instead of
by guesswork. It makes the average owner independent of the roadside repair shop when
touring. Must be seen to be appreciated. Size 25x38 inches. Printed on heavy bond paper.

'^"'^e ;Ui cents

CATALOGUE OF GOOD, PRACTICAL BOOKS 9

dern Submarine Chart— with Two Hundred Parts Numbered and Named.

A cross-section view, showii^[ clearljr and distinctly all the interior of a Submarine of the
latest type. You get more information from this chart, about the construction and opera-
tion of a Submarine, than in any other way. No details omitted — everything is accurate
and to scale. It is absolutely correct in every^ detail, having been approved by Naval En-
gineers. All the machinery and devices fitted in a modem Submarine Boat are shown, and
to make the engraving more readily understood all the features are shown in operative form*
with Officers and Men in the act of performing the duties assigned to them in service con*
ditions. This CHART IS REALLY AN ENCYCLOPEDIA OF A SUBMARINE. It
is educational and worth many times its cost. Mailed in a Tube for 25 CentS

[ Car Chart.

A chart showing the anatomy of a box car, having every part of the car numbered and its
proper name given in a reference list. Price 2S CentS

ndola Car Chart.

A chart showing the anatomy of a gondola car, having every part of the car numbered and
its proper reference name given in a reference list. Price 2& CentS

usenger-Car Chart.

A chart showing the anatomy of a passenger-car, having every part of the car numbered
and its proper name given in a reference list 2S CentS

el Hopper Bottom Coal Car.

A chart showing the anatomy of a steel Hopper Bottom Coal Car, having every part of the
car numbered and its proper name given in a reference list. Price 2S CentS

kCtlTe Power Chart.

A chart whereby you can find the tractive power or drawbar pull of any locomotive without
making a figure. Shows what cj^linders are equal, how driving wheels and steam pressure
affect the power. What sized engine you need to exert a given drawbar pull or anything you
desire in this line. Price ; 50 CentS

rse-Power Chart.

Shows the horse-power of any stationary engine without calculation. No matter what the
cylinder diameter of stroke, the' steam pressure of cut-off, the revolutions, or whether con-
densing or non-condensing, it's all there. Easy to use, accurate, and saves time and calcu-
lations. Especially useful to engineers and designers. Price ......... 50 centS

ler Boom Chart. By Geo. L. Fowler.

A chart — size 14x28 inches — showing in isometric perspective the mechanisms belonging in
a modem boiler room. The various parts are shown broken or removed, so that the internal
construction is fully illustrated. Each part is ^ven a reference number, and these, with the
corresponding name, are given in a glossary prmted at the sides. This chart is really a dic-
tionary of the boiler room — ^the names of more than 200 parts being given. Price . 25 Centft

COKE

dern Coking Practice, Including: Analysis of Materials and Products*

By J. E. Christopher and T. H. Byrom.

This, the standard work on the subject, has Just been revised. It is a practical work for those
engaged in Coke manufacture and the recovery of By-products. Fully illustrated with fold-
ing plates. It has been the aim of the authors, in preparing this book, to produce one which
shall be of use and benefit to those who are associated with, or interested in, the modem
developments of the industry. Among the ChaDters contained in Volume I are: Introduc-
tion; Classification of Fuels; Impurities of Coals; Coal Washing; Sampling and Valuation
of Coals, etc.; Power of Fuels; History of Coke Manufacture; Developments in the Coke
Oven Design; Recent Types of Coke Ovens; Mechanical Appliances at Coke Ovens; Chem-
ical and Physical Examination of Coke. Volume II covers fully the subject of By-Products.
Price, per volume f3.00 net

THE NOBMAN W. HENLEY P0BLI3HING CO .
COMPRESSED AlB

Compressed Air In All Its AppUcatlons. By Gardner O. Hiscox.

dink of.

y phaaa of the subie"pt"one can "think of. "ll nia;

ApplLBntca m whipli CompreHeed Air ia a Most Convpnicx

.PowBi lor Mflcbanioal Wotk. Railway PtopalBion, Hot r'

ComprCBged Air has lieen applied. lacludes fort^-tc

inolivs power, in ibe Operstioii of Stsiionnry
la, Air Lifts, Pumpine of Water, Acida, and
the Band BIb^ and its Work, and the tiam

HoOf.Mori

iprpssed air from isis to dale. Over 500 illuslralioiui, 5lh Editii

CONCEETE

Conerete Workers* Reference Books. A Series of Popular Handbooks for
Concrete Users. Prefjared by A. A. Houghton 50c«il8 I

The author, in preparing IhiE SEriea, has not onlu Ireal€d on the uauaj tj/peA of cOTittfvetian. but
t2:piaina and iUualralM motda and ttrvlemt that are not paienied, but vhich are £^uat in mine
ajid ojten iMpericrr to thote re^ricted bn jjalente- Thfor maids are tot/ fotitp and ch^apht "" '
structed and embody nmpiicitUw rajndUv of opertUion. and the mast auceenfvl revuks in the ffldj''A f
concrete. Each of these bookt is fully mu^aied, aad the eubjeeti are exhaustively treaUd in ph '>

Concrete Wall Forms. By A. A. Houghton.

tratcd with working drawingB. Other tj™" of i™n lo
strated and explained. (No. 1 of SerieaJ Prios M CC

By A. A. HotroBTON.

iBgonal and many oth?r styles of mosaic floor and I
!.plained- (No. 2 of Series) Price gg cc

with iUuettaliona of mold
preacDted in this book ari
nrete uID9. (No. 3 of S

Holding Concrete Clilmners, Slate and Boof IHes.

Tho mnnutacture of ail types of concrete date and roof lile

on all forma of reinforced concrete roofs are eontained nith

of concrete chimneya hy block and monolithic aystenis ia fully illuatrated and described, *

number of ornamental deaigns of cbimcey caHElruclioa uith molds are Bbown in this Ttluiblt

treatise. (No. i of Serira.J Price M «atl

Holdli^ and Coring Ornamental Concrete. By A. A. Houohton.

Tho proper proportions of oemcnt and amcgatm lor varioua finishes, alao the method <i
thk^u^iMt'that^ve^ Jon"retD'worfcBr"irill^iimrof''d^ly'!^ and value. {No. 5 of Seni*)

signs are also fully treated. (No. 6 o[ ScriES.) Price 50 CCIltS

Holding Concrete Batbtubs, Aquariums and Natalarlums. By 4. A.

Houghton.

Simplo nmlda and instmction are given for molding many atylee of concrete balhlube. swini-
miD«-pootB, etc. These molds are easily built and permit rapid and successtul work. (No. 7
of Series.) Price 50 CCnU

CATALOGUE OF GOOD, PRACTICAL BOOKS 11
onerete Bridges, Culverts and Sewers. By A. A. Houghton.

A number of ornamental concrete bridges with illustrations of molds are given. A collapuble
center or core for bridges, culverts and sewers is fully illustrated with detailed instructiona
for building. (No. 8 of Series.) Price 50 CentS

- - •

k>ii8traetiiig Concrete Porches. By A. A. Houghton.

A number of designs with working drawings of molds are full^ explained so any one can eaaly
construct di£Ferent styles of ornamental concrete porches without the purchase of expensive
molds. (No. 9 of Series.) Price 50 CCntS

folding Concrete Flower-Pots, Boxes, Jardinieres, Etc. By A. A. Houghton.

The molds for producing many original designs of flower-pots, urns, flower-boxes, jardinieres,
etc., are fully illustrated and explained, so the worker can easily construct and operate same.
(No. 10 of Series.) Price 50 CCntS

Holding Concrete Fountains and Lawn Ornaments. By A. A. Houghton.

The molding of a number of designs of lawn seats, curbing, hitching posts, pergolas, sun dials
and other forms of ornamental concrete for the ornamentation of lawns and gardens, is fidly
illustrated and described. (No. 11 of Series.) Price 50 CCntS

Concrete from Sand Molds. By A. A. Houghton.

A Practical Work treating on a process which has heretofore been held as a trade secret by
the few who possessed it, and which will successfully mold every and any class of ornamental
concrete work. The process of molding concrete with sand molds is of the utmost practical
value, possessing the manifold advantages of a low cost of molds, the ease and rapidity of
operation, perfect details to all ornamental designs, density and increased strength of the
concrete, perfect curing of the work without attention and the easy removal of the molds
regardless of any undercutting the design may have. 192 pages. Fully illustrated
Price , $2.00

Ornamental Concrete without Molds. By A. A. Houghton.

The process for making ornamental concrete without molds has long been held as a secret,
and now, for the first time, this process is ^ven to the public. The book reveals the secret
and is the only book published which explains a simple, practical method whereby the con-
crete worker is enabled, by emi>lo3dng wood and metal templates of different designs, to mold
or model in concrete any Cornice, Axchivolt, Column, Peaestal, Base Cap, Urn or Pier in a
monolithic form — bright upon the job. These may be molded in units or blocks and then built
up to suit the specifications demanded. This work is fully illustrated, with detailed engrav-
ings. Price $;S.0O

Concrete for the Farm and In the Shop. By H. Colin Campbell, C.E., E.M.

"CJoncrete for the Farm and in the Shop" is a new book from cover to cover, illustrating and
describing in plain, simple language many of the numerous applications of concrete within
the range of the home worker. Among the subjects treated are: Principles of Reinforcing;
Methods of Protecting Concrete so as to Insure Proper Hardening; Home-made Mixers;
Mixing by Hand and Machine; Form Construction, Described and Illustrated by Draw-
ings atnd Photographs; Construction of Concrete Walls and Fences; Concrete Fence Posts;
Concrete Gate Posts; Corner Posts; Clothes liine Posts; Grape Arbor Posts; Tanks;
Troughs; Cisterns; Hog Wallows; Feeding Floors and Barnyard Pavements; Foundations;
Well Curbs and Platforms; Indoor Floors; Sidewalks; Steps; Concrete Hotbeds and Cold
Frames; Concrete Slab Roofs; Walls for Buildings; Repairing Leaks in Tanks and Cisterns;
and all topics associated with these subjects as bearing upon securing the best results from
concrete are dwelt upon at sufficient length in plain every-day English so that the inexperi-
enced person desiring to imdertake a piece of concrete construction can, by following the
directions set forth in this book, secure 100 per cent, success every time. A number of con-
venient and practical tables for estimating quantities, and some practical examples, are also
given. (5x7.) 149 pages. 51 illustrations. Price 75 CentS

opular Handbook for Cement and Concrete Users. By Mybon H. Lewis.

This is a concise treatise of the principles and methods employed in the manufacture and use
of cement in all classes of modern worI». The author has brought together in this work all
the salient matter of interest to the user of concrete and its many diversified products. The
matter is presented in logical and systematic order, clearly written, fully illustrated and free
from involved mathematics. ^ Everything of value to the concrete user is given, including
kinds of cement employed in construction, concrete architecture, inspection and testing,
waterproofing, coloring and painting, rules, tables, working and cost data. The book com-
prises thirty-three chapters, as follow: Introductory. Kinds of Cement and How They
are Made. Properties. Testing and Requirements of Hydraulic Cement. Concrete and Its
Properties.^ Sand, Broken Stone and Gravel for Concrete. How to Proportion the Materials.
How to Mix and Place Concrete. Forms of Concrete Construction. The Architectural and
Artistic Possibilities of Concrete. Concrete Residences. Mortars, Plasters and Stucco,
and How to Use Them. The Artistic Treatment of Concrete Surfaces. Concrete Build

12 THE NORMAN W. HENLEY PUBLISHING CO.

Blocks. The Making of Ornamental Concrete. Concrete Pipes, Fences, Posts, etc. E^seo-
tial Features and Advantages of Reenforced Concrete. How to Desi^ Reenforced Con*
Crete Beams, Slabs ^d Columns. Explanations of the Methods and f^mciples in Designing
Reenforced Concrete, Beams and Slabs. Systems of Reenforcement Employed. Keen-
forced Concrete in Factory and General Building Construction. Concrete in Foimdation Work.
Concrete Retaining Walls, Abutments and Bulkheads. Concrete Arches and Arch Bridges.
Concrete Beam and Girder Bridges. Concrete in Sewerage and Draining Works. Concrete
Tanks, Dams and Reservoirs. Concrete Sidewalks, Curbs and Pavements. Concrete in
Railroad Construction. The Utility of Concrete on the Farm. The Waterproofing of Con-
crete Structures. Grout of Liquid Concrete and Its Use. Inspection of Concrete Work.
Cost of Concrete Work. Some of the special features of the book are: 1. — ^The Attention
Paid to the Artistic and Architectural Side of Concrete Work. 2. — ^The Authoritative Treat-
ment of the Problem of Waterproofing Concrete. 3. — ^An Excellent Summary of the Rules
to be Followed in Concrete Construction. 4. — ^The Valuable Cost Data and Useful Tables
given. A valuable Addition to the Library of Every Cement and Concrete User. , Price . |2^

WHAT IS SAID OF THIS BOOK:

"The field of Concrete Construction is well covered and the matter contained is well within
the understanding of any person." — Engineering-Contracting.

"Should be on the bookshelves of every contractor, engineer, and architect in the land."—
National Builder.

Waterproofing: Concrete* By Myron H. Lewis.

Modem Methods of Waterproofing Concrete and Other Structures. A condensed statement
of the Principles, Rules, and Precautions to be Observed in Waterproofing and Dampproofing
Structures and Structural Materials. Paper binding. Illustrated. I^ce .... 50 C6IltS

DICTIONARIES

Aviation Terms, Termes D'Aiiation, English-French, French-English.

Compiled by Lieuts. Victor W. Pag6, A.S., S.C.U.S.R., and Paul Mon-
TARiOL, of the French Flying Corps, on duty on Signal Corps Aviation School,
Mineola, L. I.

The lists contained are confined to essentials, and special folding jplates are included to show
all important airplane parts. The lists are divided in four sections as follows: 1. — Flying
Field Terms. 2. — ^The Airplane. 3. — The Engine. 4. — ^Tools and Shop Terms.
A complete, well illustrated volume intended to facilitate conversation between English-speak-
ing and French aviators. A. very valuable book for all who are about to leave for duty ove^
seas.

Approved for publication by Major W. G. Kilner, S.C, U.S.C.O. Signal Corps Aviation School,
Hazelhurst Field, Mineola, L. I. This book should be in everv Aviator's and Mechanic's Kit
for ready reference. 128 pages, fully illustrated, with detailed engravings. Price . . $1.00

Standard Electrical Dictionary. By T. O'Conor Sloane.

An indispensable work to all interested in electrical science. Suitable alike for the student
and professional. A practical handbook of reference containing definitions of about 5,000
distinct words, terms and phrases. The definitions are terse and concise and include every
term used in electrical science. Recently issued. An entirely new edition. Should be in
the possession of all who desire to keep abreast with the progress of this branch of science.
Complete, concise and convenient. 682 pages, 393 illustrations. Price $3*00

DIES— METAL WORK

Dies: Their Construction and Use for the Modern Worldng of Sheet Met&ls.

By J. V. WOODWORTH.

A most useful book, and one which should be in the hands of all engaged in the press working
of metals; treating on the Designing, Constructing, and Use of Tools, Fixtures and Devices,
together with the manner in which they should be used in the Power Press, for the cheap and
rapid production of the great variety of sheet-metal articles now in use. It is desinned
as a guide to the production of sheet-metal parts at the minimum of cost with the
maximum of output. The hardening and temoering of Press tools and the classes of work
which may be produced to the best advantage by the use of dies in the power press are fully
treated. Its 515 illustrations show dies, press fixtures and sheet-inetal working devices, the
(IcHfriptions of which are so clear and practical that all metal-working mechanics will be able
to iindorstand how to design, construct and use them. Many of the dies and press fixtures
treated wore either constructed by the author or under his supervision. Others were built by
skilful mechanics and are in use in large sheet-metal establishments and machine shops.
6th Revised and Enlarged Edition. Price $3*00

CATALOGUE OF GOOD, PRACTICAL BOOKS 13

anehes. Dies and Tools for Manufacturing In Presses. By J. V. Wood-
worth.

This work is a oompanion volume to the author's elemental^ work entitled "Dies: Their
Construction and Use." It does not go into the details of die-making to the extent of the
author's previous book, but gives a comprehensive review of the field of operations carried on
by presses. A large part of the information given has been drawn from the author's personal
experience. It might well be termed an Encyclopedia of Die-Making, Punch-Making, Die-
Sinking, Sheet-Metal Working, and Making of Special Tools, Sub-presses, Devices and Mechani-
cal Combinations for Punching, Cutting, Bending, Forming, Piercing, Drawing, Compressing
and Assembling Sheet-Metal Parts, and also Articles of other Materials in Machine Tools.
2d Edition. Price $4.00

*op Forstns, Dle-Slnklng and Machine-Forming of Steel. By J. V.

WOODWORTH.

This is a practical treatise on Modem Shop Practice, Processes, Methods, Machine -Tools,
and Details treating on the Hot and Cold Machine-Forming of Steel and Iron into Finishea
Shapes; together with Tools, Dies, and Machinery involved in the manufacture of Duplicate
Forgings and Interchangeable Hot and Cold Pressed Parts from Bar and Sheet Metal. This
book fills a demand of long standing for information regarding drop-forgings, die-sinking and
machine-forming of steel and the shop practice involved, as it actually exists in the modem
drop-forging shop. The processes of die-sinking and force-making, which are thoroughly
described and illustrated m this admirable work, are rarely to be found explained in such a
clear and concise manner as is here set forth. The process of die-sinking relates to the engrav-
ing or sinkinjg of the female or lower dies, such as are used for drop-forgings, hot and cold
machine-forging, swedging, and the press working of metals. The process of force-making
relates to the engraving or raising of the male or upper dies used in producing the lower dies
for the press-forming and machine-forging of duplicate parts of metal.

In addition to the arts above mentioned the book contains explicit information regarding the
drop-forging and hardening plants, designs, conditions, equipment, drop hammers, forging
machines, etc., machine forging, hydramic forging, autogenous welding and shop practice.
The book contains eleven chapters, and the information contained in these chapters is just
what will prove most valuable to the forged-metal worker. All operations described in the
work are thoroughly illustrated by means of i>er8pective half-tones and outline sketches of
the machinery employed. 300 detailed illustrations. Price $2S*50

DRAWING— SKETCHING PAPER

letical PerspectiTe. By Richards and Colyin.

Shows just how to make all kinds of mechanical drawings in the only practical perspective
isometric. Makes everything plain, so that any mechanic can understand a sketch or drawing
in this way. Saves time in the drawing room, and mistakes in the shops. Contains practicsJ
examples of various classes of work. 4th Edition. Price 50 CentS

lear Perspective Self-Tauglit. By Hebhian T. C. Kraus.

This work gives the theory and i^ctice of linear perspective, as used in architectural, en^neer- ,
ing and mechanical drawing. Persons taking up the study of the subject by themselves will'
be able, by the use of the instruction given, to readily grasp the subject, and by reasonable
practice become good p>er8pective draftsmen. The arrangement of the book is good ; the plate
IS on the left-hand, while the descriptive text follows on the opposite page, so as to be readily
referred to. The drawings are on sufficiently large scale to show the work clearly and are
plainly figured. There is included a self-explanatory chart which gives all information neces-
sary for the thorough understanding of perspective. This chart alone is worth many times
over the price of the book. 2d Revised and Enlarged Edition. Price $2S*50

f-Tauslit Mechanical Drawing and Elementary Macliine Design* By

F. L. Sylvester^ M.E., Draftsman, with additions by Erik Oberg, associate
editor of " Machinery."

This is a practical treatise on Mechanical Drawing and Machine Design, comprising the first
principles of geometric and mechanical drawing, workshop mathematics, mechanics, strength
ot materials and the calculations and design of machine details. The author's aim has been
to adapt this treatise to the requirements of the practical mechanic and young draftsman
and to present the matter in as clear and concise a manner as possible. To meet the demanded
of this class of students, practically all the important elements of machine design have been
dealt with, and in addition algebraic formulas have been explained, and the elements of
trigonometry treated in the manner best suited to the needs of the practical man. The book
isdivided into 20 chapters, and in arranging the material, mechanical drawing, pure and simple,
has been taken up first, as a thorough understanding of the principles of representing objects
facilitates the further study of mechanical subjects. This is followed by the mathematics
necessary for the solution of the problems in machine design which are presented later, and a
practical introduction to theoretical mechanics and the strength of materials. The various
elements entering into machine design, such as cams, gears, sprocket-wheels, cone pulleys,
bolts, screws, couplings, clutches, shafting and fly-wheels, have been treated in such a way
as to make possible the use of the work as a text-book for a continuous course of study. It
is easily comprehended and assimilated even by students of limited previous training. ****"
pages, 215 engravings. Price ' |

THE NORMAN

HENLEY PUBLISHING CO.

§ A New SketchlBK Pftper.

A DEW Bpenally ruled pmier to enable ,
d ^win^^M it'Siak J'ouo"Bke'wbX tl

Is u wpll s* for assEiatil^

Pwb of 4Di>bfetfi, 9il2 Inches
40 Bheclfc 12ilH Incbes.

ELECTRICITY

■.Arithmetic of Electrielt}'< By Prof. T. O'CoNon Sloane.

Bl Ion

1 of ,hU )d]

practic^ PToblema, with detailed si
useful works published on the ecii

bnical formulas. ZOth Edilion.

Commatator Consfructlan. By Wu. Baxtbk,

Tbc business end of any djmamo or □
book goes into the desiBninE, buHdio^

raedylh

lofusi

n for .

inii presa or latfae. '
The book ie illiuti

:?"''!''!.

eration°L°'ofMrly'°deBEnb€d. iS
■atle; Hheo uwd ea a malor il wlO

onlmary work. The book ie illustrated with more thao

DyMmo."" 2" Side Beanng Rods.'^a. ■Field"punchinf
Pulley. 7. Brueh Holdeie. S. Connection Board.
11. .\rmatun Winding. 12. Field Winding. 13. Coi

Paper. Price

Cloth. PrioB

Electric Bells. By M. B. Suseper.

a. ehowiu 0*
1. Fmy*»«

ie for the i

a, Then

BuTgl.

Both tne eiecincian ana ini
In their work. Toola, be!l>
thermoBtata, eireuit break-
Ecribed from the etandi

rom the Btandpoinla oi
>n lor building ibe appan
tieal worker will find the chapter on ^ir'
Upkeep oi aysteiPB. and the Loration of

:r will find in thia book sew material whieh ia easHitiil

leu- applieation, eonstruction and repair. The delailsl
■*■ "^" appeal t*j the experimenter partjeularly.

00 Wiring, Calculation of ^ire Biiea and Ma<i«t

Battenee tor Small In
ConitmetiDn of An nun
Elaborate Dell Systemt

>rk; How and Why Bell Worii;
dilations; Making Bella and Push Buttona: Wiring Bell Eyrimai;
lators and Signals; Burglary Alarms and Auidliary Apparatus; Mon
Finding Faults and Remedying Them, 124 pages, hilly illustnted.

"••« SO tent*

Electric Llgbtlng and HeatbiK Pocket Book. By Sydngy F. Walker.

This book puts In convenient form useful information regardins the apparatus which la liktlT

eluded and useful eloctrica
in leather. Pocket book fo

■ 93.M

Hubjcct. Praetiral. every-day pre'-' ■-■ --' — ' "-

ing inlelligcnt reaulla clearly ahoi
pie t'lplanation with reference 1«

eisaple arcuii ie dcTeloped with the pnaitbi

fod'^Tibii

used. Ohm's law is given 1

CATALOGUE OF GOOD, PRACTICAL BOOKS 15

as a part of a wiring plan and their employment in house wiring clearly illustrated. Some
simple facte about testing are included in connection with the wiring. Molding and conduit
work are civen careful consideration; and switchboards are systematically treated, built up
and illustrated, showing the purpose they serve, for connection with the circuits, and to shimt
and compound wound machines. The simple principles of ^ switchboard construction, the
development of the switchboard, the connections of the various instruments, including the
lightning arrester, are also plainly set forth.

Alternating current wiring is treated, with explanations of the power factor, conditions calling
for various sizes of wire, and a simple way of obtaining the sizes for single-phase, two-phase
and three-phase circuits. This is the only complete work issued showing and telling you what
you should know about direct and alternating curl^nt wiring. It is a ready reference. The
work is free from advanced technicalities and mathematics, arithmetic being used throughout.
It is in every respect a handy, well-written, instructive, comprehensive volume on wiring
for the wireman, foreman, contractor, or electrician. 2nd Revised Edition. 303 pages, 130
illustrations. Price 91*50

metric Furnaces and their Industrial Applications. By J. Wright.

-This is a book which will prove of interest to many classes of people; the manufacturer who
desires to know what product can be manufactured successfully m the electric furnace, the
chemist who wishes to post himself on the electro-chemistry, and the student of science who
merely looks into the subject from curiosity. New, Revised and Enlarged Edition. 320
pages. Fully illustrated, cloth. Price $3*00

ictric Toy Making, Dynamo Building, and Electric Motor Construction.

By Prof. T. O'Conor Sloane.

This work treats of the making at home 9f electrical tosns, electrical apparatus, motors, dynamos*
and instruments in general, and is designed to bring within the reach of young and old the
manufacture of genuine and useful electrical appliances. The work is especially designed for
amateurs and young folks.

Thousands of our young people are daily experimenting, and busily engaged in making elec-
trical toys and apparatus of various kinos. The present work is just what is wanted to give
the much needed information in a plain, practical manner, with illustrations to make easy
the carrying out of the work. 20th Edition. Price $1*00

USllcal Electricity. By Prof. T. O'Conor Sloans.

This work of 768 pa^ was previously known as Sloane*s Electricians*^ Hand Book, and^ is
intended for the practical electrican who has to make things go. The entire field of electricity
is covered within its pages. Among some of the subjects treated are: The Theory of the
Electric Current and Circuit, Electro-Chemistry, Primary Batteries, Storage Batteries,
Generation and Utilization of Electric Powers, Alternating Current, Armature Winding,
Dynamos and Motors, Motor Generators, Operation of the Central Station Switchboards,
Safety Appliances, Distribution of Electric Light and Power, Street Mains, Transformers,
Arc and incandescent Lighting, Electric Measurements, Photometry, Electric Railways,
Telephony, Bell-Wiring, Electno-Platin^, Electric Heating, Wireless Telegraphy, etc. It
contains no useless theory; everything is to the point. It teaches you just what you want
to know about electricity. It is the standard work published on the subject. Forty-one
chapters, 556 engravings. Price {R3.50

ctriclty Simplified. By Prof. T. O'Conor Sloane.

The object of ^"Electricity Simplified" is to make the subject as plain as possible and
to show what the modern conception of electricity is; to show how two plates of different
metal, immersed in acid, can send a message around the globe; to explain how a bundle of
copper wire rotated by a steam engine can be the agent in lighting our streets, to tell what the
volt, ohm and ampere are, and what high and low tension mean; and to answer the questions
that perpetually arise in the mind in this age of electricity. 13th Edition. 172 pages. Illus-
trated. Price yi.OO

use Wiring. By Thomas W. Poppe.

This work describes and illustrates the actual installation of Electric Light Wiring, the man-
ner in which the work should be done, and the method of doing it. The book can be con-
veniently carried in the pocket. It is intended for the Electrician, Helper and Apprentice.
It solves all Wiring Problems and contains nothing that conflicts with the rulings of the
National Board of Fire Underwriters. It gives just the information essential to the Success-
ful Wiring of a Building. Among the subjects treated are: Locating the Meter. Panel-
Boards. Switches. Plug Receptacles. Brackets. Ceiling Fixtures. The Meter Connec-
tions. The Feed Wires. The Steel Armored Cable System. The Flexible Steel Conduit
System. The Ridig Conduit System. A digest of the National Board of Fire Underwriters*
rules relating to metallic wiring systems. Various switching arrangements explained^ and
diagrammed. The easiest method of testing the Three- and Four-way circuits explained.
The pounding of all metallic wiring systems and the reason for doing so shown and erolained.
The insulation of the metal parts of lamp fixtures and the reason for the same described and
illustrated. 125 pages. 2nd Edition, revised and enlarged. Fully illustrated. Flexible
cloth. Price 50 ce*

THE NORMAN W. HENLEY PUBLISHING CO.

J Become a SuccessTul Electrician. By Prof. T. O'Conob Sldake.

Ivtry yquna man who wiah^ to become b Bucceeaful elsctridao Bhoutd read tiia boot. It

F Han^emeat of DynamoB. By Lummis-Paterson.

A haodhook of theory and practice. Thia work jb arrangod
coveni the elementary theory at the dynamo. Tbc anconi ni

le parts. The finl part
, „..ile the third part rel^lH

4th Edition. 292 pagee, 117 illuettaitionB. Price

I Standard Electrical Dlctlonarr. By T. O'Conor Sloans.

An indisHnsabla norli to sll intcreslod in ckctricid science. Suitable alike for t
and, profeceional. A praclical handbook of reference oontaining deGoitiDos of al

postiesBion ^ aJl who dc^re to keep abreaat with thn progresn of this branch (^ &
ita Hjrangemflnt and typography the book is veiy convenient. The word oT Vetm
printed in black-faced typ^ which nadily catches ths eye, nhile the body at the

□an-tsclmical nadei. The gen
then amplify and e^Uin in a

ik is readily made. It is

actly wordcc

Di of Gfly pais

an of words, reference to the proper place in the bod;
fieult to decide how far a book of thia character h tc
imo_the_encyclopedU ton ""

defiaidons aie

□ceded; for other purposH,
aatisfy both demanOB, and dc
12th ^kiition.

|MI

Storage Batteries Simplified. By Victor W. Faq^, M.E.

The greatly incrsaeing application of trtoraga ^tteries m modem' enBincering and mechamal
work has created a demand for a book that ntll consider this subject eompletely and eidu-
Bively. This is the most thorough and autboHtative treatise ever published on this labiMt.

"nd rebuild storage batteries but also outlines all the indusi

B ropainnat

marine ajiplicatione, etc. This book telle how Uiey are used in central station standby hi
Btorage battery is outlined in thit tiEBtiee. 320 pages, fully illustrated. Price , . . fl^jl

Switchboards. By William Baxter, Jr.

TK, bnnli appeals to every engineer and electrician who wants (o know the practiral udr

hieh volta^ boanU foi

power lranamie«on. ^ u ^n,on^

Telephone Construction, Installation, Wlrlns, Operation and Maintenance'

By W. H. Radolifpe and H. C, Cubhino.

This book is intended lor the amateur, the wireman, or the engineer who desires lo eslahliMh

CATALOGUE OP GOOD, PRACTICAL BOOKS 17

contains definitions of units and terms used in the text. Selected wiring tables, which are very
helpful, are also included. Among the subjects treated are Construction, Operation, and
Installation of Telephone Instruments;^ Inspection and Maintenance of Telephone Instru-
ments; Telephone Line Wiring; Testing Telephone Line Wires and Cabl^ Wiring and
Operation of Special Telephone Sjrstems, etc. 2nd Edition, Revised and Enlarged. 223
154 illustrations 91«06

ireless T^egraphy and Telephony Simply Explained. By Alfred P.
Morgan.

This is undoubtedly one of the most complete and comprehensible treatises on the subject
ever published, and a dose study of its pages will enable one to master all the details of the
wireless transmission of messages. The author has filled a long-felt want and has succeeded
in furnishing a lucid, comprehensible explanation in simple language of the theory and practice
of wireless telegraphy and telephony.

Among the contents are: Introductory; Wireless Transmission and Reception — The Atrial
System, Earth Connections — ^The Transmitting Apparatus, Spark Coils and Transformers*
Condensers, Helixes, Spark Gaps, Anchor Gaps, Aerial Switches — ^The Receiving Apparatus,
Detectors, etc. — ^Tuning and Coupling, Tuning Coils, Loose Couplers, Variable Condensers,
Directive Wave Sjrstems — Miscellaneous Apparatiis, Telephone Receivers, Range of Stations,
Static Interference — ^Wireless Telephones, Sound and Soimd Waves, The Vocal Cords and
Ear — ^Wireless Telephone, How Sounds Are Changed into Electric Waves — Wireless Tele-
phones, The Apparatus — Summary. 154 pages, 156 engravings. Price $1*00

Iring a House* By Herbert Pratt.

Shows a house already built; tells Just how to start about wiring it; where to begin; what
wire to use; how to run it according to Insurance Rules; in fact, just the information you
need. Directions apply equally to a shop. 4th Edition. Price ^ Ceuts

FACTORY MANAGEMENT, ETC.

)deni Machine Shop Construction, Equipment and Management. By

O. E. Perriqo, M.E.

The only work published that describes the modem machine shop, or manufacturing plant
from the time the grass is growing on the site intended for it until the finished product is
shipped. By a careful study of its thirty-two chapters the practical man may economically
bund, efficiently equip, and successfully manage the modern machine shop or manufacturing
establishment. Just the book needed by those contemplating the erection of modem shop
buildings, the rebuilding and* reorganization of old ones, or the introduction of modem shop
methods, time and cost ssrstems. It is a book written and illustrated by a practical shop
man for practical shop men who are too busy to read theories and want faita. It is the most
complete all-around book of its kind ever published. It is a practical book for practical men,
from the apprentice in the shop to the president in the office. It minutely describes and i\-
lustrates the most simple and yet the most efficient time and cost sjrstem jret devised. 2nd
Revised and Enlarged Edition, just issued. 384 pages, 219 UlustratioDS. Price . . . ^.00

FUEL

mbustion of Coal and the Prevention of Smoke* By Wm. M. Barr.

This book has been prepared with special reference to the generation of heat by the com-
bustion of the common fuels found in the United States, and deals particularly with the con*
ditions necessary to the economic and smokeless combustion of bituminous coals in Stationary
and Locomotive Steam Boilers.

The presentation of this important subject is systematic and progressive. The arrangement
of the book is in a series of practical questions to which are appended accurate answers, which
describe in language, free from technicalities, the several processes involved in the furnace
combustion of American fuels; it clearly states the essential requisites for perfect combustion,
and points out the best methods for furnace construction for obtaining the greatest quantity
of heat from any given quality of coal. Nearly 350 pages, fully illustrated. Price . . ^1,00

LOke Prevention and Fuel Economy. By Booth and Kershaw.

A complete treatise for all interested in smoke prevention and combustion, being ba:>)d on
the German .work of Ernst Schmatolla, but it is more than a mere translation of the German
treatise, much being added. The authors show as briefly as i>oseible the principles of fuel
combustion, the methods which have been and are at present in use, as well as the proper
scientific methods for obtaining all the energy in the coal and burning it without smoxe.
Considerable space is also given to the examination of the waste gases, and several of the
representative English and American mechanical stoker and similar appliances are described.
The losses carried away in the waste gases are thoroughly analyzed and discussed in the Ap-
pendix, and abstracts are also here given of various patents on combustion apparatus. The
book is complete and contains much of value to all who have charge of large plants. 194 pap««.
Illustrated. Price §38.

Cobs

drre

the theory h

Kfl

THE NORMAN W. HENLEY PUBLISHING CO.
GAS ENGINES AND GAS

, GasoUne and Oil Engines. ISy GASD>rE:R D, Hiscox. Revised b
Victor W, PAuii, M.E.

Just issued Xbw 1918 Editjon. Reviaed sod Enlsrced. Every user o[ i
thiaboak. ample, instnictivH and tight up-K^ate. The ouly eompleta n

_ cpBUios^ cscti es ™nu_y ^ '!!'^!.^^*^j QT'iu"formB of eiplowve nioton fnr iB
ilanes and motDr-trycIn, Includes aim PrudDEfl
Lt^tioEiB for all gtodenta. Aoa-eD^ne owDfTi, pO' I

(Tavinei, many Hperiall}' made from en£iD»^ I
dcBwiOES, au in coneet praportioD. oou pages, 435 CDsravincs. Pnue ■ . . ■ fZ^Vl'

The Gasoline Engine on the Farm: Its Operation, Bepair and ITses.
Xeno W. Putnam.

Thia is a prartiral truiti^ on the Gaeoline and Kerosene Engine Intended fpi the msn
wanta to know irat how lo manage hia engine and how to apply it to all kinda oi fan

Thia book abounds with hints and helps for the farm and Buggestiona for the home and
wife, Thei-e ia so mueh of value in this book that it is itnpoBaible to adequately de»

and eveiy farm home ou^t to have. Includes selecting t^e moat suitable engine fc
work, its moat convenient and efficient iiiBtallalJon. with chapters on troubles, their ni

harvesting and toad grading are fully eove^d; also plain directionH ate given for h

applyine power to the disagreeable small tasks which must otherwise be done bv hand,

home-made contrivsnena for cutting wood, supplying ki

loadii^, hauling and unloading hay. delivering grain t(

eluded; also full directions for makin g the engme mil,^ •*■•, vut-c, .-

house and clean the windows, etc. Very fully illustrated with drawing

cute showing Stationary. Portable and Tractor EnRiiiiiB doing all kii

book*'' fl'is'^n BiTto''th?rM3t''gettetr'nVBl'ilable"- -^-^°-'*'- J^--™
smith, implement dealer and, in fact, all who can
gasoline engiaea or gas tiactors to advantage. 6;iO pai

WHAT IS SAID OF THIS BOOK:

"Am much pleased with the book and find it to be very complete and up^-tf^date. [ wiLE
heartily reoommend it to students and farmerB whom I think would stand in need of sucli ■
work, as I think it b an eiceptionally good one."— iV. S. Gardiner. Prof, in Charge, ClomKii
Agr. College of B. C. ; Dept. of Agri. and Agri. E^p. Station, Clemson College, S. C
"I feel that Mr. Putnam's book covei? the main points which a farmer ahoold know." — B- T-
Burdick, Instructor ia Agronomy, Uaivereity of Vermont, Burlington. Vt.

describing what the GasoUne Engine is; its eonati

how to soleet it; how to use it and how to remedy tro

Operators and Users of Gasoline Motors of all kinds, 'lliis work fully d

various types of Gasoline Engines used in Motor Boats, Motor Vehii

The parU, acceasories and appliances are described with chapters on

operation and engine troubles. Special attention is given to the e

of motors, with useful hinta and suMeations on emersency repaita , ..

plcto glDBSary of technical terms anTan alphabetically arranged table of IroubloB and thai

symptoma form moat valuable and unique features of thia manual '■ ' "

in the hook ia original, having been made by the author. Ever"
vnlue. A book which you cannot afford to be without. 275
engravings. Price

Gas Engine Construction, or How to Build a Half-horsepower Gas Engine

By Parbell and Weed,

A praetical treatise of 3(W pages describing the theory and principiea of (he action of C,u
Engines of various types and the design and constniction of a half-hofsepowcr Cas Eslin'-
with illustrations of the work in actual progress ,. together with the dimensioned working dra*-

and the amateur mechanic. This bnnk trMta d tho c,T>.lH,t ..^^^r. f-,.... ii.. ><nn,<~i^f ^

of the Gas Engii

le ia taken
1. 300 mu.

CATALOGUE OF GOOD, PRACTICAL BOOKS 19

•w to Bun and Install Two- and Foiir-Cycle Marine Gasoline Engines.

By C. Von Culin.

Revised and enlarged edition just issued. The object of this little book is to furnish a pocket
instructor for the beginner, the busy man who uses an engine for pleasure or profit, but who
does not have the time or inclination for a technical book, but simply to thoroughly under-
stand how to properly operate, install and care for his own engine. The index refers to each
trouble, remedy, and subject alphabetically. Being a quick reference to find the cause, remedy
and prevention for troubles, and to become an expert with his own engine. Pocket size.
Paper binding. Price 25 eeutS

idem Gas Engines and Producer Gas Plants. By R. E. Mathot.

A guide for the gas engine designer, user, and engineer in the construction, selection, purchase,
installation, operation, and maintenance of gas engines. More than one book on gas engines
has been written, but not one has thus far even encroached on the field covered by this book.
Above all, Mr. Mathot's work is a practical guide. Recognizing the need of a volume that
would assist the gas engine user in understanding thoroughly the motor upon which he depends
for power, the author has discussed his subject without the help of any mathematics and with-
out elaborate theoretical explanations. Every part of the gas engine is described in detail,
tersely, clearly, with a thorough understanding of the requirements of the mechanic. Help>-
ful suggestions as to the purchase of an engine, its installation, care, and operation, form a
most valuable feature of the work. 320 pages, 175 detailed illustrations. Price . . . ^.50

e Modem Gas Tractor* By Victor W. Pag6, M.E.

A complete treatise describing all types and eaztis of gasoline, kerosene and oil tractors.^ Con-
siders design and construction exhaustively, gives complete instructions for care, operation and
repair, outlines all practical applications on the road and in the field. The best and latest
work on farm tractors and tractor power plants. A work needed by farmers, students, black-
smiths, mechanics, salesmen, implement dealers, designers and engineers. 2nd Edition, Re-
vised. 504 pages, 228 illustrations, 3 folding plates. Price $^*00

GEARING AND CAMS

vel Gear Tables* By D. Ac. Engstrom.

- A book that will at once commend itself to mechanics and draftsmen. Does away with all
the trigonometry and fancy figuring on bevel gears, and makes it easy for anyone to lay them
out or make them just right. There are 36 full-page tables that show every necessary dimen-
sion for all sizes or combinations jrou're apt to need. No puzzling, figuring or guessing. Gives
placing distance, all the angles (including cutting angles), and the correct cutter to use. A
copy of this prepares you for anything in the bevel-gear line. 3rd Edition. 66 pages.
Pnce 11.00

ange Gear Devices. By Oscar E. PerRigo.

A practical book for every designer, draftsman, and mechanic interested in the invention and
development of the devices for feed changes on the different machines requiring such mechanism.
All the necessary information on this subject is taken up, analyzed, classified, sifted, and con-
centrated for the use of busy men who have not the time to go through the masses of irrelevant
matter with which such a subject is usually encumbered and select such information as will
be useful to them.

It shows just what has been done, how it has been done, when it was done, and who did it.
It saves time in hunting up patent records and re-inventing old ideas. 88 pages. 3rd Edition.
Price 11.00

iftlng of Cams. By Louis Rouillion.

The lasdng out of cams is a serious problem unless you know how to go at it right. This puts
you on the right road for practically any kind of cam you are likely to nm up against. 3rd
Edition. Price 35 CCntS

HYDRAULICS

Iraullc Engineering. By Gardner D. Hiscox.

A treatise on the properties, power, and resources of water for all purposes. Including the
measurement of streams, the fiow of water in pipes or conduits; the horsepower of falling water,
turbine and impact water-wheels, wave motors, centrifugal, reciprocating and air-lift pumps.
With 300 figures and diagrams and 36 practical tables. All who are interested in water-works
development will find this book a useful one, because it is an entirely practical treatise un^n
a subject of present importance and cannot fail in having a far-reaching influence, and f<^"
reason should have. a pla6e in the working libraiy of' every engineer. Among the »
treated are: Historical Hydraulics; Properties of Water; Measurement of the Flow at 8<

20 THE NORMAN W. HENLEY PUBLISHING CO.

Flow from Sub-surface Orifices and Nossles; Flow of Water in Pipes; Siphons of Varioos
Khids^ Dams and Great Storage Reservoirs; City and Town Water Supply; Wells and Their
Reinfotcement; Air-lift Methods of Raising Water; Artesian Wells; Irrigation of Arid Dis-
tricts; Water Power; Water Wheels; Pumps and Pumping Machinery ; Reciprocating Pumpe;
Hydraulic Power Transmission; Hydraulic Mining; Canals; Ditches; Conduits and Pipe
Lines; Marine Hydraulics; Tidal and Sea Wave Power, etc. 320 pages. Price . . . |4,^

ICE AXD REFRIGERATION

Pocketbook of ReMgeration and Ice Making. By A. J. Wallis-Tatlob.

This is one of the latest and most comprehensive reference books published on the subject of
refrigeration and cold storage. It explains the properties and refrigerating effect of the dif-
ferent fluids in use, the management of refrigerating machinery and the construction and insu-
lation of cold rooms with their required pipe surface for different degrees of cold; freesinc
mixtures and non-freezing brines, temperatures of cold rooms for all kinds of provisions, cold
storage charges for all classes of goods, ice making and storage of ice, data and memoranda
for constant reference by refrigerating engineers, with nearly one hundred tables containing
valuable references to every fact and condition required in the installment and operation of a
refrigerating plant. New edition just published. Price $1.50

INVENTIONS— PATENTS

Inventors* Manual: How to Make a Patent Pay*

This is a book designed as a guide to inventors in perfecting their inventions, taking out their
patents and disposing of them. It is not in any sense a Patent Solicitor's Circular nor a Patent
Broker's Advertisement. No advertisements of any description appear in the work. It is a
book containing a quarter of a century's experience of a suocessfm inventor, together with
notes based upon the experience of many other inventors.

Among the subjects treated in this work are: How to Invent. How to Secure a Good Patent.
Value of Good Invention. How to Exhibit an Invention. How to Interest Capital. How
to Estimate the Value of a Patent. Value of Design Patents. Value of Foreign Patents.
Value of Small Inventions. Advice on Selling Patents. Advice on the Formation of Stock
Companies. Advice on the Formation of Limited Liability Companies. Advice on Disposing
of Old Patents. ^ Advice as to Patent Attornesrs. Advice as to Sellizig Agents. Forms M
Assignments. License and Contracts. State Laws Concerning Patent Rights. 1900 Census
of the United States by Counts of Over 10,000 Population. Revised Edition. 120 pages.
Price .:.... 11.00

KNOTS

Knots, Splices and Rope Work. By A. Hyatt Verhill.

This is a practical book giving comple'te and simple directions for making all the most useful
and ornamental knots in common use, with chapters on Splicing, Pointing, Seising, Serving,
etc. This book is fully illustrated with 154 original engravings, Which show how each knot,
tie or splice is formed, and its appearance when finished. The book will be found of the greatest
value to Campers, Yachtsmen, Travelers, Boy Scouts, in fact, to anyone having occasion to
use or handle rope or knots for any purpose. The book is thoroughly reliable and practical,
and is not only a guide, but a teacher. It is the standard work on the subject. Among tfauB
contents are: 1. Cordage, Kinds of Rope. Construction of Rope, Parts of Rope Cable and
Bolt Rope. Strength of Rope, Weight of Rope. 2. Simple Knots and Bends. Terms Used
in Handling Rop>e. Seizing Rope. 3. Ties and Hitches. 4. Noose, Loops and Mooring
Knots. 5. Shortenings, Grommets and Salvages. 6. Lashings, Seizings and Splices. 7.
Fancy Knots and Rope Work. 128 pages, 150 original engravings. 2nd Revised Edition.

i*rice 75 eents

LATHE WORK

Lathe Design, Construction, and Operation, with Practical Examples ol
Lathe Work. By Oscar E. Perrigo.

A new, revised edition, and the only complete American work on the subject, written by i
man who knows not only how work ought to be done, but who also knows how to do it, anc
how to convey this knowledge to others. It is strictly up-tondate in its descriptions anc
illustrations. Lathe history and the relations of the lathe to manufacturing are given
also a description of the various devices for feeds and thread -cutting mechanisms from earh
efforts in this direction to the present time. Lathe design is thoroughly discussed, includ
ing back gearing, driving cones, thread-cutting gears, and all the essential elements of thi
modern lathe. The classification of lathes is taken up, giving the essential differences o
the several types of lathes including, as is usually unaerstood, engine lathes, bench lathes
speed lathes, forge lathes, ^ap lathes, puUey \aWieft, iotnvVu^ \«.\>Ck«», Ti\>a\\\:Q\ft-«^iQdle lathes
rapid-reduction lathes, precision lathes, turret \at\iea, wp^c\»\ \«btVve», ^wXTtfiaJ^-^j ^xvM^ciNsb^t^bss

CATALOGUE OF GOOD, PRACTICAL BOOKS 21

etc. In addition to the complete exposition on ccmstniction and design, much practical
matter on lathe installation, care and operation has oeen incorporated in tiie enlarged new
edition. All kinds of lathe attachments for drilling, milling, etc., are described and com-
plete instructions are given to enable the novice machinist to grasp the art of lathe operation
as well as the principles involved in design. A number of difficult machining operationB
are described at length and illustrated. The new edition has nearly 500 pages and 350 illus-
trations. Price $9*50

WHAT IS SAID OF THIS BOOK:

"This is a lathe book from beginning to end, and is just the kind of a book which one de-
lights to consult — a masterly treatment of the subject in hand." — Engineering News.
**This work will be of exceptional interest to any one who is interested in lathe practice, as
one very seldom sees such a complete treatise on a subject as this is on the lathe."— Cana-
dian Machinery.

Actical Metal Turning. By Joseph G. Horner.

A work of 404 pages, fully illustrated, covering in a comprehensive manner the modern prac-
tice of machining metal ^rts in the lathe, including the regular^ engine lathe, its essential
design, its uses, its tools, its attachments, and the manner of holding the work and perform-
ing the operations. The modernised engine lathe, its methods, tools and great rjinfln nf accu-
rate work. The turret lathe, its tools, accessories and methods of performmg its functions.
Chapters on special work, grinding, tool holders, speeds, feeds, modem tool steels, etc.
Second edition '. , $3«50

irnlng and Boring Tapers. By Fred H. Colvin.

There are two ways to turn tapers; the right way and one other. This tr^tise has to do
with the right way; it tells you how to start the work properly, how to set the lathe, what
tools to use and how to use them, and forty and one other little things that you should know.
Fourth edition 1^ CentS

LIQUID Am

luld Air and the Liquefaction of Gases. By T. O'Conor Sloane.

This book gives the history of the theory, discovery and manufacture of Liquid Air, and

contains an illustrated description of all the experiments that have excited the wonder of

audiences all over the country. It shows how liquid air, like water, is carried hundreds of

miles and is handled in open buckets. It tells what may be expected from it in the near

iuture.

A book that renders simple one of the most perplexing chemical problems of the century.

Startling developments illustrated by actual experiments.

It is not only a work of scientific interest and authority, but is intended for the general reader,

being written in a popular style — easily understood by every one. Second ^tion. 365

pages. Price. $2.00

LOCOMOTIVE ENGINEEBIN6

'-Brake Catechism. By Robert H. Blackall.

This book is a standard text-book. It covers ^ the Westinghouse Air-Brake Equipment,
including theT^o. 5 and the No. 6 E.-T. Locomotive Brake Equipment; the K (Quick Ser-
vice) Triple Valve for Freight Service; and the Cross-Compound Pump. The operation of
all parts of the apparatus is explained in detail, and a practical way of finding their pecu-
liarities and defects, with a proper remedy, is given. It contains 2,000 questions with their
answers, which will enable any railroad man to pass any examination on the subject of
Air Brakes. Endorsed and used by air-brake instructors and examiners on nearly every
railroad in the United States. Twenty-sixth edition. 411 pages, fully illustrated with
colored plates and diagrams. Price £3.00

lerican Compound Locomotives. By Fred H. Colvin.

The only book on compounds for the engineman or shoioman that shows in a plain, prac-
tical way the various features of compound locomotives in use. Shows how they are made,
what to do when they break down or balk. Contains sections as follows: A Bit of History.
Theory of Compounding Steam Cylinders. Baldwin Two-Cylinder Compound. Pittsburg
Two-Cylinder Compound. Rhose Island Compound. Richmond Compound. Rogers Com-

g^und. Schenectady Two-Cylinder Compound. Vauclain Compound. Tandem Compounds,
aldwin Tandem. The Colvin-Wightman Tandem. Schenectady Tandem. Balanced
Locomotives. Baldwin Balanced Compound. Plans for Balancing. Locating Blows.
Breakdowns. Reducing Valves. Drifting. Valve Motion. Disconnecting. Power of Com-
pound Locomotives. Practical Notes.

Fully illustrated and containing ten special "Duotone" inserts on heavy Plate Paper, ~
ing different types of Compounds. 142 pages. Price

THE NORMAN W. HENLEY PTTBLTSHTNO CO.

[ AppllGatian of Hlghlf Superheated Steam to Locomotives. By I
Ga&be.

A pmotiffBl book wbirb amaot be recommended ton lughlj- to thoaa li . . ^ _

tfn on Gonrmtian ol Highly Superhealeil Sleain; BupErlieat«i Staaa anil the Two-CyUnJ

C^lracll'i*'"Detaila'o?°Loc^mQli'yea Uamg Hiehly' Sui»r^Eatcd SMm™" Eiqierl'ii
WcirkiDg Results. Illustrated with foIdinE plalea sml tablet). Cloth. Prioe . . .

Clombnstloii of Coal and the PreTentlon of Smoke. By Wm. M. Babb.

mon fucle found ia the United States and deals i
' Id the cuinamio and Emokeless cambuEtion of bi

Tide book has been prepared with apecial refnent^ to the Eeueration of heat by the roin-fl
buBtipp o[ tho common fuela found in the United Statoo and deole particularly wi-- -■-■

Preaeotation of this important subjer
dncribe in lanauaiie fTce from teobn .

tioa. and poinla out the beat methoils of furnace eonatnictiou for obtaininff the freauot
quantity of beat frntn Boy civen quality o[ coal. Nearly 360 paEEH. fully iUuBtntsL
fri" |l.lt

Diary of a ftomid-House Foreman. By T. S. Reillt.

BffSS"rmiL. 'mt^™." Price " . !! .".''.'^.°'!'':°''*"^".''*'"':'.\*.''I'°|ijt

link Motions, Valves and Talve Setting. By Fubd H. Colvtn, Associate Editor
of "American Machinist."
A handy book for the cnKin^r or machSniat that cleam op the myateriee of Tolve ectliDe.

of different types are iUufltralfld and eiplaiaed. A book that every railroad man ia the
motive-power department ouirht to have. Containa chapters on Loeomotlve link Motjoa,
Vaive Movements, Setting Slide Valvcg, Analyais by Diagrams, Modem Practice, SUp cf
Block. Slice Valves. Piston Valvea, Setting Piston Valves. Joy-Allen Valve Gear. Walachaoil
ValvB Gear. Goocb Valve Gear. AlftHt-fltibbell Valve Gear, etc., etc. Fully illustnled.

i^ice 50 cents

Locomotive Boiler Construction. By Fran^ A. Ki^einhans.

The construetioQ of boilers ia general is treated and, following thia. the loeomotlve bolo'
b taken up in the order in which its various parts eo IhrouEh the ehop. Shows all tt-ps
of boilers used; gives details of CDTistruction: practical facts, such as life of riveting, puarba
and diesi work done per day, ailouancc for bending and flanging sheets and other diU.

their ansners for Government Inspectors. Contains chapters on LayingJDut Work; Fil-
ing and Forgini; Funehins: Shearing: Plate Planinc; General Tables: Finlsbinc Puti:
Bending; Machinery ParlA; iUvetiog; Boiler DetailB: Smoke-Box Details, Aensmbliiif
and Calking; Boiler-Shop Machinery, etc., etc.

There isn't a man who has anything 1<i do with bt^er work, either new or repair work, who
doesn't need this book. The manufacturer, superintendent, foreman and boiler WDik«—
all need it. No matter what the type of bloler, you'll find a mint of iutormatioB Ihatjm
wouldn't be without. Over 400 pases, five large folding plates. Price fiM

Locomotive Breakdowns and their Bemedles. By Geo. L. Fowi,eb. Be-

viscil by Wm. W, Wood, j\ir-Brake Inatructor, Just issued Revised poeke*

It it out of the question to try and tell you about every subject that is coversi in this foM
edition of Locomotive Breakdowns, Just inisginn all the common troubles that u enftaiHr
may eipect to happen some time, and then add all of the unexpected ones, traiibla Chat Hvl
occur, but that you have never thought about, and you will find that they are all trealol vttb
the very best methods of repair, Walschaert Locomotive Valve Gear Troubles, Elertnl
Headlight Troubles, as well as Questions and Answers on the Air Broke are aU induded. Ill
pages. Sth Revised Edition. Fully illustrated. Price ||,H

Locomotive Catechism. By Robert Gbimshaw.

The revised edition of "Locomotive Catechism," by Robert Grimehaw, Is a New Book Inn
Cover to Cover, It pontaina twice BB many pases and double the number of illuslratiom o!
previous editions. Includes the greatest amount of practical information ever published ca
the construction and management of modern locomotives. Specially Prepared Chapti'rs os
the Walsebaert Locomotive Valve Gear, the Air-Brake Etiuipment and the BUectrie Hesdligbt

CATALOGUE OF GOOD, PRACTICAL BOOKS 23

It commends itself at once to every Engineer and Fireman, and to idl who are going in for
examination or promotion. In plam language, with full, complete answers, not only .all the
questions asked by the examining engineer are given, but those which the young and leas
experienced would ask the veteran,^ and which old hands ask as "stickers." It is a veritable
Encyclopedia of the Locomotive, is entirely free from mathematics, easily understood and
thoroughly up to date. Contains over 4,000 Examination Questions with their Answers.
825 pages, 437 illustrations, and 3 folding plates. 28th Revised Edition. Price ^.50

aetical Instructor and Reference Book for Locomotive Firemen and
Engineers* By Chas. F. Lockhabt.

An entirely new book on the Locomotive. It appeals to every railroad man, as it tells him
how things are done and the right way to do them. Written by a man who has had years of
practical experience in locomotive shops and on the road firing and running. The information
given in this book cannot be found in any other similar treatise. Eight hundred and fifty-one
questions with their answers are included, which will prove specially helpful to those preparing
for examination. Practical information on: The Construction and Operation of Locomotives,
Breakdowns and their Remedies, Air Brakes and Valve Gears. Rules and Signals are handled
in a thorough manner. As a book of reference it cannot be excelled. The book is divided
into six parts, as follows: 1. The Fireman's Duties. 2. General Description of the Locomotive.
3. Breakdowns and their Remedies. 4. Air Brakes. 5. Extracts from Standard Rules.
6. Questions for Examination. The 851 questions have been carefully selected and arranged.
These cover the examinations required by the different railroads. 368 pages, 88 illustrations.
Price 11.50

erention of Railroad Accidents, or Safety in Railroading. By George
Bradshaw.

This book is a heart-to-heart talk with Railroad Employees, dealing with facts, not theories,
and showing the men in the ranks, from every-day experience, how accidents occur and how
they may be avoided. The book is illustrated with seventy original photographs and drawings
showing the safe and unsafe methods of work. No visionary schemes, no ideal pictures.
Just Plain Facts and Practical Suggestions are given. Every railroad employee who reads the
book is a better and safer man to have in railroad service. It gives just the information which
will be the means of preventing many injuries and deaths. All railroad employees should
procure a copy, read it, and do their part in preventing accidents. 169 pages. Poeket size.
Fully illustrated. Price .gQ centS

tin Rule Examinations Made Easy. By G. E. Collingwood.

This is the only practical work on train rules in print. Every detail is covered, and puzzling

¥>ints are explained in simple, comprehensive language, making it a practical treatise for the
rain Dispatcher, Engineman, Trainman, and all others who have to do with the movements
of tndns. Contains complete and reliable information of the Standard Code of Train Rules
for single track. Shows signals in Colors, as used on the different roads. Explains fully the
practical application of train orders, giving a clear and definite understandir^ vf all orders
which may be used. The meaning and necessity for certain rules are explain^ in such a
manner that the student may know beyond a doubt the rights conferred under any orders he
may receive or the action required by certain rules. As nearly all roads require trainmen to
pass regular examinations, a complete set of examination questions, with their answers, are
mcluded. These will enable the student to pass the required examinations with credit to
himself and the road for which he works. 2nd Edition, Revised. 256 pages, fully illustrated,
with Train Signals in Colors. Price 91»!35

e Walschaert and Other Modem Radial ValTe Gears for Locomotives.

By Wm. W. Wood.

If you would thoroughly understand the Walschaert Valve Gear you should possess a copy
of this book, as the author takes the plainest form of a steam engine — a stationary eiigine in
the rough, that will only turn its crank in one direction — and from it builds up, with the read-
er's help, a modern locomotive equipped with the Walschaert Valve Gear, complete. The
points discussed are clearly illustratea: ^ Two large folding plates that show the posUioBs of
the valves of both inside or outside admission type, as well as the links and other parts of the
^ear when the crank is at nine different points in its revolution, are especially valuable in mak-
mg the movement clear. These employ sliding cardboard models which are contained in a
pocket in the coyer.

The book is divided into five general divisions, as follows: 1. Analysis of the gear. 2. De-
signing and erecting the gear. 3. Advantages of the gear. 4. Questions and answers relating
to the Walschaert Valve Gear. 5. Setting valves with the Walschaert Valve Gear; the three
primary types of locomotive valve motion ; modern radial valve gears other than the Wal-
schaert ; the Hobart All-free Valve and Valve Gear, with questions and answers on breakdowns:
the Baker-Pilliod Valve Gear; the Improved Baker-Pilliod Valve Gear, with questions and
answers on breakdowns.

The questions with full answers given will be especially valuable to firemen and engineers in
preparing for an examination for promotion. 245 pages. 3rd Revised Edition. iSrice $1,50

24 THE NORMAN W. HENLEY PUBLISHING CO.

Westinghouse E-T Air-Brake Instruction Pocket Book. By Wm. W. WooDp
iUr-Brake Instructor.

Here is a book for the railroad man, and the man who aims to be one. It is without doi
the only complete work published on the Westinghouse "E-T Locomotive Brake Equipment^
Written by an Air-Brake Instructor who knows just what is needed. It covers the subjer^
thoroughly. Eversrthing about the New Westinghouse Engine and Tender Brake Equig
ment, including the standard No. 5 and the Perfected No. 6 style of brake, is treated in deti
Written in plam English and profusely illustrated with Colored Plates, which enable one
trace the flow of pressiires throughout the entire equipment. The best book ever publiali
on the Air Brake. Equally good for the beginner and the advanced engineer. Will pass aoj
one through any examination. It informs and enlightens you on every point. Indi4)ensabil
to every engineman and trainman.

Contains examination questions and answers on the E-T equipment. Covering what the E-T
Brake is. How it shoiild be operated. What to do when defective. Not a question can bt
asked of the engineman up for promotion, on either the No. 5 or the No. 6 E-T equipment
that is not ask^ and answered m the book. If you want to thoroughly understand the E-'
equipment get a copy of this book. It covers every detail. Makes Air-Brake troubles a~

examinations easy. Price ^1,

•

MACHINE-SHOP PRACTICE

American Tool Making and Intercliangeable Manufacturing. By J. V.

WOODWORTH.

A "shoppy" book, containing no theorising, no problematical or experimental devices. Thert
are no badly proportioned and impossible diagrams, no catalogue cuts, but a valuable (»Uee<
tion of drawings and descriptions of devices, the rich fruits oi the author's own experienMi
In its 500-odd pages the one subject only. Tool Making, and whatever relates thereto, is dealt
with. ^ The work stands without a rival. It is a complete, practical treatise, on the art pi
American Tool Making and system of interchangeable manufacturing as carried on to-day is
the United States. In it are described and illustrated all of the different types and classes of
small tools, fixtures, devices, and special appliances which are in general use in all machine*
manufacturing and metal-working establishments where economy, capacitYi and interchan^
ability in the production of machined metal parts are imperative. Tne science of jig makini
i« exhaustively discussed, and particular attention is paid to drill jigs, boring, profiling ara
milling iBxtures and other devices in which the parts to be machined are located and fastened
within the contrivances. All of the tools, fixtures, and devices illustrated and described havi
been or are used for the actual production of work, such as parts of drill presses, lathes, patented
machinery, typewriters, electrical apparatus, mechanical appliances, brass goods, compositioil
parts, mould products, sheet-metal articles, drop-forgings, jewelry, w&tches, medals, corns, ete.
531 pages. Price $4,111

HENLEY'S ENCYCLOPEDIA OF PRACTICAL ENGINEERING AND ALLIED
TRADES. Edited by Joseph G. Horner, A.M.I., M.E.

This set of five volumes contains about 2,500 pages with thousands of illustrations, including
diagrammatic and sectional drawings with full explanatory details. This work covers the
entire practice of Civil and Mechanical Engineering. The best known experts in all branches
of engineering have contributed to these volumes. The Cyclopedia is admirably well adapted
to the needs of the beginner and the self-taught practical man. as well as the mechanicsl
engineer, designer, draftsman, shop superintendent, foreman, and machinist. The work will
be found a means of advancement to any progressive man. It is encyclopedic in scope, thor-
ough and practical in its treatment on technical subjects, Bimple ana clear in its descriptive
matter, and without unnecessary technicalities or formulse. The articles are as brief as may
be and yet give a reasonably clear and esrplicit statement of the subject, and are written by
men who have had ample practical experience in the matters of which they write. It tells
you all you want to know about engineering and tells it so simply, so clearly, so concisely, thai
one cannot help but understand. As a work of reference it is without a peer. Complete
set of five volumes, price fSStll

The Modern Machinist. By John T. Usher.

This is a book, showing by plain description and by profuse engravings^ made expreesly for
the work, all that is best, most advanced, and of the highest efficiency in modern macnin^
shop practice, tools and implements, showing the way by which and through which, >8^',;
Maxim says, "American machinists have become and are the finest mechanics in the ''O'*!;
Indicating as it does, in every line, the familiarity of the author with every detail of daily
experience in the shop, it cannot fail to be of service to any man practically connected with
the shaping or finishing of metals.

There is nothing experimental or visionary about the book, all devices being in actual laa
and giving good results. It might be called a compendium of shop methods, showing •
variety of special tools and appliances which will give new ideas to many mechanics, from
the superintendent down to the man at the bench. It will be found a valuable addition to
any machini.st's library, and should be consulted whenever -a new or difficult job is to be
done, whether it is boring, milling, turning, or planing, as they are all treated in a practical
manner. Fifth edition. 320 pages. 250 illustrations. Price $2*M

CATALOGUE OF GOOD, PRACTICAL BOOKS 25

THE WHOLE FIELD OF MECHANICAL MOVEMENTS
COTEBED BT MB. HISCOX'S TWO BOOKS

We publish two hooka by Oardner D. Hiaeox that vritt keep you from "inventino" thinge that have
been done before, and euoQtat roaye of doing thinge that you have not thought of before. Many a
man ependa time emd money pondering over eome metMonical problem^ only to learn, after he
has aocoed the T^oblem, that the aame thing hoe been aeeomiMeKed and put in pradiee by others
long before. Time emd money vpent in €m effort to accomplish tohat has already been aeeompiisbed
are time and money LOST. The tohole field of medyanics, every knovm mechanical movement,
and praetiajMy every device are covered by these two books. If the thing you v>ant has been invented,
it is iUti^at^i in them. If it hasn't been invented, then you'll find in them tAe nearest thinjQS
to tvhat you toant, some movements or devices that toill apjdy in your case, verhaps; or tohtdi
will give you a key from which to voork. No book or set of Books ever published is of more real
value to the Inventor, Draftsman, or practical Mechanic than the ttvo mdumes dewribed below.

«^iilcal MoTementSy Powers, and DeTlces. B^ Gardner D. Hiscox.

This is a collection of 1,890 engravings of different mechanical motions^ and appliances, ao*
companied by appropriate text, making it a book of great value to the inventor, the drafts-
man, and to all reaaers with mechanical tastes. The book is divided into eighteen sections
or chapters, in which the subject-matter is classified under the following heads: Mechanical
Powers; Transmission of Power; Measurement of Power; Steam Power; Air Power Appli-
ances; Electric Power and Construction; Navigation and Roads; Gearing; Motion and
Devices' Controlling Motion; Horological; Mining; Mill and Factory Appliances; Con-
struction and Devices; Drafting Devices; Miscellaneous Devices, etc. 15th Edition. 400
octavo pages. Price $3«00

tehanlcal Appliances, Mechanical Movements and Novelties of Construc-
tion. By Gardner D. Hiscox.

This is a supplementary volume to the one upon mechanical movements. Unlike the first
volume, which is more elementary in character, this volume contains illustrations and de-
scriptions of many combinations of motions and of mechanical devices and appliances found
in different lines of machinery, each device being shown by a line drawing with a description
showing its working parts and the method of operation. From the multitude of devices de-
scribed and illustrated might be mentioned, in passing, such items as conveyors and elevators.
Pony brakes, thermometers, various types of boilers, solar engines, oil-fuel burners, condensers,
evaporators, Corliss and other valve gears, governors, gas engines, water motors of various
descriptions, air ships, motors and dynamos, automobile and motor bicycles,^ railway lock
signals, car couplers, link and gear motions, ball bearings, breech-block mechanism for heavy
guns, and a large accumulation of others of equal importance. One thousand specially made
engravings. 396 octavo pages. Fourth edition. Price $3*00

ichlne-Shop Tools and Shop Practice. By W. H. Vandervoort.

A work of 555 pages and 673 illustrations, describing in every detail the construction, opera-
tion and manipulation of both hand and machine tools. Includes chapters on filing, fit-
ting and scraping surfaces; oh drills, reamers, taps and dies; the lathe ana its tools: planers,
shapers, and their tools; milling machines and cutters; gear cutters and gear cutting; drill-
ing machines and drill work; grinding machines and their work; hardening and tempering;
gearing, belting and transmission machinery; useful data and tables. Sixth edition.
Price $3.00

ichlne-Shop Arithmetic. By Colvin-Cheney.

This is an arithmetic of the things you have to do with daily. It tells you plainly about:
how to find areas in figures; how to find surface or volume of balls or spneres; handy waj^
for calculating; about compound gearing; cutting screw threads on any lathe; drilling for
taps; speeds of drills; taps, emery wheels, grindstones, milling cutters, etc.; all about the
Metric system with conversion tables; properties of metals; strength of bolts and nuts;
decimal equivalent of an inch. All sorts of machine-shop figuring and 1,001 other things,
any one of which ought to be worth more than the price of this book to you, as it saves you
the trouble of bothering the boss. 6th Edition. 131 pages. Price 50 CCntS

^ern Machlne-Shop Construction, Equipment and Management. By

Oscar E. Perrigo.

The only work published that describes the Modem Shop or Manufacturing Plant from the
time the grass is growing on the site intended for it until tne finished product is shipped. Just
the book needed by those contemplating the erection of modern shop buildings, the rebuilding
and reorganization of old ones, or the introduction of Modern Shop Methods, time and cost
systems. It is a book written and illustrated by a practical shop man for practical shop men
who are too busy to read theories and want facts. It is the most complete all-round hook nf
. its kind ever published. Second Edition, Revised. 384 large quarto pages. 219 original ai
specially made illustrations. 2nd Revised and Enlarged Edition. Price ^Ji

THE NORMAN W. HENLEY PUBLISHING CO,

Their DeslKii) Construction, and Opend

Thu book ducribes and ill

in &ad fo[«iga. 301 pages, 300 illuBtmtioiu. Cloth. Priu

" Shop Kinks." By Robeki Gbimbhaw.

A book of 400 pagFa and 222 [lIuBtrAtiDOB, b
machinp-shop prsctice. Departing from coi
or tummoli shop usage and limitBliia work t

St[vp%*4&lHSei.tr™ the world Me"3a(

itireV diffsrent from any other book on
iiial style, the author avoida univcnil

CAult tha advancod methods of r?pr?9«n-

, ~ diapaaal of tha reader. This book sIiom

..- _ ^_ -.mnga arfl pa»i{blfl» aod how prodanta may be unproved- To
holds out BUEgeBtiona that, properly applied, will haiten his advancemfnl.
rord_ to be. without it. .It bristles with valuable wrinkles and helpful eueE»-

study its pages. Hfth edition

- $S^

Threads and Thread Cutting. B7 Colvin ajid Stabel.

Tills clears up many of the mysteries of Chread^outtbg, such as double and. ti
tables. ThLd 'e.£tion!'^ri™. . !'. !^ .". . .'I . . .! .^' . . . .™. .". . ?

MANUAL TRAINING

Economics of Manual Training. By Loms Rodilijon.

The oaly book published tiiat gives just the information needed by alt interested in Minud
Trainlujc. regardiua Buildings. Equiprtient, and Supplies. Shows exactly what a atedfd
for all eradee of toe work from the Kindergarten to the High and Normal Ecbrwl. Gives
itemised lists of everything used in Manual Training Work and tells just what it ouBhl U

MARINE ENGINEERING

The Naral Architect's and Shlpbutldor's Pix-ket Book of Formulsc, BuIfs.
and Tables and Marine Engineer's and Surveyor's Handy Boob of

Reference. By Clement Mackhow and lAayo WooLt.AaD.

The eleventh Revised and Enlarged Edition of this most conipreheniiive work baa just bea
^' ~i absolutely indispenRable to all engaged in tlie Shipbuilding Industry, at it Cfln-
' ' -- all dala and form ulse that are ordindrily rHiuired. The book »

.. 790 Pi

..«5.Hnet

Marine Engines and Boilers: Their Design and ConstmctloD. By Dft. (•■

Bapbr, Lbslle S. Robertson and 8. Bhyan Donkin. ]

In the words of Dr. Bauer, t)ic present work awes its origin to an oft felt want of a condFDK'l

. Thet

Itbym

periencelrhe faet that So original CJcmian work was written by the ehiet engmrer d
famous Vulcan Works, Stettin, a in ilaelt a guaranlee that this boalc is in all respects i(
oughly up-toyialB, and that it embodies all the information whieh is neofiasary lorU* iei
and construction o( the highest types of marine eneinea siid boilors. It may be said thai
motive power which Dr. Bauer has placed in the fast Gprman liners that hove been turatd
of lale veais from the Stettin Works recrpsent the very best praeticB in manne engineenni
roughly systemalJe, theoreti rally sou

of tl

phot

raphi

-implt---'

. 7Mpi

tables. Cloth. Prioo t».W net

CATALOGUE OP GOOD, PRACTICAL BOOKS 27

MINING

re Deposits, with a Chapter on Hints to Prospectors. By J. P. Johnson.

Thia book gives a condensed Account of the ore deposits at present known in South Africa.
It is also intended as a guide to the prospector. Only an elementary knowledge of geology
and some mining experience are necessarj^ in order to understand this work. With these
qualifications, it will materially assist one in his search for metalliferous mineral occurrences
and, so far as simple ores are concerned, should enable one to form some idea of the possi-
bilities of any he may find. Illustrated. Cloth. Price $!3«00

actical Coal Mining. By T. H. Cockin.

An important work, containing 428 pages and 213 illustrations, complete with practical details,
which will intuitively impart to the reader not only a general knowledge of the principles
of coal mining, but also considerable insight into allied subjects. The treatise is positively
ui>-to-date in every instance, and should be in the hands of every colliery^ engineer, geologist,
mine operator, superintendent, foreman, and all others who are interested in or connected with
the industry. 3d Edition. Cloth. Price $2.50

lydcs and Chemistry of Mining. By T. H. Bybom.

A practical work for the use of all preparing for examinations in mining or qualifjang for
colliery managers' certificates. The aim of the author in this excellent book is to place clearly
before the reader useful and authoritative data which will render him valuable assistance in
his studies. The only work of its kind published. The information incorporated in it will
prove of the greatest practical utility to students, mining engineers, colliery managers, and
all others who are specially interested in the present-<lay treatment of mining problems. 160
pages, illustrated. Price $!3«00

PATTERN MAKING

actical Pattern Maldng. By F. W. Barrows.

This book, now in its second edition, is a comprehensive and entirely practical treatise on the
subject of pattern making, illustrating pattern work in both wood and metal, and with definite
instructions on the use of plaster of paris in the trade. It ^ives specific and detailed descrip-
tions of the materials used by pattern makers, and describes the tools, both those for the
bench and the more interesting machine tools, having complete chapters on the Lathe, the
Circular Saw, and the Band Saw. It gives many examples of pattern work,^ each one fully
illustrated and explained with much detail. These examples, in their great variety, offer much
that will be found of interest to all pattern makers, and especially to the younger ones, who
are seeking information on the more advanced branches of their trade.

In this second edition of the work will be found much that is new, even to those who have
long practised this exacting trade. In the description of patterns as adapted to the Moulding
Machine many difficulties which have long prevented the rapid and economical production of
castings are overcome; and this great, new branch of the^ trade is given much space. Strip-
ping plate and stool plate work and the less expensive vibrator, or rapping plate work, are
all explained in detail.

Plain, every-da^ rules for lessening the cost of patterns, with a complete system^ of cost
keeping, a detailed method of marking, applicable to all branches of the trade, with com-
plete information showing what the pattern is, its specific title, its cost, date of production,
material of which it is made, the number of pieces and core-boxes, and its location in the
pattern safe, all condensed into a most complete card record, with cross index.
The book closes with an original and practical method for the inventory and valuation of
patterns. Containing nearly 350 pages and 170 illustrations. Price ^.00

PERFUMERY

rfumes and Cosmetics: Their Preparation and Manufacture. By G. W.

AsKiNSON, Perfumer.

A comprehensive treatise, in which there has been nothing omitted that could be of value
in *,he perfumer or manufacturer of toilet preparations. Complete directions for making
handkerchief jperfumes, smelling-salts, sachets, fumigating pastilles; preparations for the
care of the skin, the mouth, the hair, cosmetics, hair dj^es and other toilet articles are given,
also a detailed description of aromatic substances; their nature, tests of purity, and whole-
some manufacture, including a chapter on synthetic products, with formulas for their use.
A book of general as well as professional interest, meeting the wants not only of the drug-
gist and periume manufacturer, but also of the general public.^ Among the contents are:
1. The History of Perfumery. 2. About Aromatic Substances in General. 3. Odors from
the Vegetable Kingdom. 4. The Aromatic Vegetable Substances Employed in Perfumery,

6. The Aniqial Substances Used in Perfumery. 6. The Chemical Products Used in Perfumery.

7. The Extraction of Odors. 8. The Special Characteristics of Aromatic Substances. 9. T*
Adulteration of Essential Oils and Their Recognition. 10. Sjmthetic Products. 11. T»'
of Physical Properties of Aromatic Chemicals. 12. The Essences or Extracts Employ
in Perfumery. 13. Directions for Making the Most Important Essences and Extc«

28 THE NORMAN W. HENLEY PUBLISHING CO.

14. The Division of Perfumery. 15. The Manufacture of Handkerchief Perfumes. 16. For-
mulas for Handkerchief Perfumes. 17. Ammoniacal and Acid Perfumes. 18. Dry Pe>
fumes. 19. Formulas for Dry Perfumes. 20. The Perfumes Used for Fumigation. 21. An-
tiseptic and Therapeutic Value of Perfumes. 22. Classification of Odors. 23. Some Special
Perfumer^r Products. 24. Hygiene and Cosmetic Perfumenr. 25. Preparations for the Care
of the Skin. 26. Manufacture of Casein. 27. Formulas for Emulsions. 28. Formulas for
Cream. 29. Formulas for Meals, Pastes and Vegetable Milk. 30. Preparations Used for
the Hair. 31. Formulas for Hair Tonics and Ilestorers. 32. Pomades and Hair Oib. »
33. Formulas for the Manufactiire of Pomades and Hair Oils. 34. Hair Dyes and Dqnlar f*
tories. 35. Wax Pomades, Bandolines and Brilliantines. 36. Skin Cosmetics aod
Face Lotions. 37. Preparations for the Nails. 38. Water Softeners and Bath Salts. 39.
Preparations for the Care .of the Mouth. 40. The Colors Used in Perfumery. 41. The Uten-
sils Used in the Toilet. Fourth ^tion, much enlarged and brought up to date. Nearly
400 pages, illustrated. Price |5t00

WHAT IS SAID OF THIS BOOK:

"The most satisfactory work on the subject of Perfumery that wc have ever seen."
"We feel safe in saying that here is a book on Perfumery that will not disappoint you, for
it has practical and excellent formula that are within your ability to prepare readily."
"We recommend the volume as worthy of confidence, and say that no purchaser will be dis-
appointed in securing from its pages good value for its cost, and a large dividend on the same,
even if he should use but one per cent, of its worldng formulse. There is money in it for every
user of its information." — Pharmaceutical Record.

PLUMBING

Mechanical Drawing for Plumbers. By R. M. Starbuck.

A 'oncise, comprehensive and practical treatise on the subject of mechanical drawing in its l
mrious modern applications to the work of all who are in any wav connected with the plumb-
in,^ trade. Nothmg will so help the plumber in estimating and in explaining work to cus-
tomers and workmen as a knowledge of drawing, and to the workman it is of inestimable
value if he is to rise above his position to positions of greater responsibility. Among the
chapters contained are: 1. Value to plumber of knowledge of drawing; tools requirea and
their use; common views needed in mechanical drawing. 2. Perspective versus mechanical
drawing in showing plumbirg construction. 3. Correct and incorrect methods in plumbing
drawing; plan and elevation explained. 4. Floor and cellar plans and elevation; scale
drawings; use of triangles. 5. Use of triangles; drawing of fittings, traps, etc._ 6. Drawing
plumbing elevations and fittings. 7. Instructions in drawing plumbing elevations. 8. The
drawing of plumbing fixtures; scale drawings. 9. Drawings of fixtures and fittings. 10. Ink-
ing of drawmgs. 11. Shading of drawings. 12. Shading of drawings. 13. Sectional drawings;
drawing of threads. 14. Plumbing elevations from architect's plan. 15. Elevations of sepa-
rate parts of the plumbing system. 16. Elevations from the architect's plans. 17. Drawings
of detail plumbing connections. 18. Architect's plans and plumbing elevations of residence.
19. Plumbing elevations of residence {continued) ; plumbing plans for cottage. 20. Plumbing
elevations; roof connections. 21. Plans and plumbing elevations for six-flat building. 22.
Drawing of various parts of the plumbing system; use of scales. 23. Use of architect's scales.
24. Special features in the illustrations of country plumbing. 25. Drawing of wrought-iron
piping, valves,, radiators, coils, etc. 26. Drawing of piping to illustrate heating systems.
150 illustrations. Price fl«50

Modem Plumbing Illustrated. By R. M. Starbuck.

This book represents the highest standard of plumbing work. It has been adopted and used
as a reference book by the United Stat^ Government in its sanitary work in Cuba, Porto
Rico and the Philippines, and by the principal Boards of Health of the United States and
Canada.

It gives connections, sizes and working data for all fixtiires and groups of fixtures. It is help-
ful to the master plumber in demonstrating to his customers and in figuring work. It flves
the mechanic and student quick and easy access to the best modem plumbing practice. Sog-
gestions for estimating plumbing construction are contained in its pages. This book repre*
sents, in a word,. the latest and best up-to-<late practice and should oe in the hands of eveiy
architect, sanitary engineer and plumber who wishes to keep himself up to the minute on
this important feature of construction. Contains following chapters, each illustrated with a
oiU-page plate: Kitchen sink, laundry tubs, vegetable wash sink; lavatories, pantry sinUi
contents of marble slabs; bath tub, foot and sitz bath, shower bath; water closets. ^^^^
of water closets; low-down water closets, water closets operated by flush valves, water closet
range; slop sink, urinals, the bidet; hotel and restaurant sink, grease trap; refrigerators,
safe wastes, laundry waste, lines of refrigerators, bar sinks, soda fountain sinks; horse stall,
frost-proof water closets; connections for S traps, venting; connections for drum traps;
soil-pipe connections; supporting of soil pipe; main trap and fresh-air inlet; floor drains and
cellar drains, subsoil drainage; water closets and floor connections; loc&l venting] connecUoos
for bath rooms; connections for bath rooms, continued; examples of poor practice; rougnmi
work ready for test; testing of plumbing systems; method of continuous venting: continuous
venting for two-floor work; continuous venting for two lines of fixtures on three or more
floors; continuous venting of water closets; plumbing for cottage house; construction for
cellar piping; plumbing for residence, use of special fittings; plumbing for two-flat hoiMe;
plumbmg for apartment building, plumbing for double apartment building; plumbing 'or
oflSce building; plumbing for public toilet rooms; plumbing for public toilet rooms, con*
tinned; plumbing for bath establishment; plumbing for engine house, factory plumbif4j
automatic flushing for schools, factories, etc.; use of flushing valves; urinals for public toiig
rooms; the Durham system, the destmcaon ot pii^tes by electrolysis; construction of woes

CATALOGUE OF GOOD, PRACTICAL BOOKS 29

without use o^ lead; automatic sewage lift; automatic sump tank; country plumbing;
construction oi cesspools; septic tank and automatic sewage siphon; water supply for
country house; thawmg of wat^ mains and service by electricity; double boilers; hot
water supply of large building; automatic control of hot- water tank; suggestions for
estimating plumbing construction. 407 octavo pages, fully illustrated by 57 full-page
engravings. Third, revised and enlarged edition, just issued. Price 9^«00

uidard Practical Plomblns* By R. M. Stabbuck.

A complete practical treatise of 450 pages, covering the subject of Modem Plumbing in all its
branches, a large amotmt of space being devoted to a very complete and practical treatment of
the subject of Hot Wat^ Supply and Circulation and Range Boiler Work. Its thirty chapters
include about every phase of the subject one can think of, makiTig it an indispensable work to
the master plumber, the joumejrman plumber, and the apprentice plumber,^ (Containing chap-
ters on: the plumber's tools; wiping solder; composition and use; joint wiping; lead work;
traps; siphonage of traps; venting; continuous venting; house sewer and sewer connections;
house drain; soil piping, roughing; main trap and fresh air inlet; floor, yard, cellar drains,
rain leaders, etc. ; fixture wastes; water closets; ventilation; improved plumbing connections;
residence plumbing; plumbing for hotels, schools, factories, stables, etc.; modem country
plumbing; filtration of sewage and water supply; hot and cold supply; range boilers; circula-
tion; circulating pipes; range boiler problems; hot water for large buildings; water lift and
its use; multiple connections for hot water boilers; heating of radiation by supply sjrstem;
theory for the plumber; drawing for the plumber. Fully illustrated by 347 engravings.
Price $3.00

RECIPE BOOK

nley's Twentieth Century Book of Kecipes, Formulas and Processes.

Edited by Gardner D. Hiscox.

The most valuable Techno-chemical Formula Book published, including over 10,000 selected
scientific, chemical, technological, and practical recipes and processes.

This is the most complete Book of Formulas ever published, giving thousands of recipes for
the manufacture of valuable articles for everyday use. Hints, Helps, Practical Ideas, and
Secret Processes are revealed within its pages. It covers every branch of the useful arts and
tells thousands of ways of making money, and is just the book everyone should have at his
command.

Modern in its treatment of every subject that properly falls within its scope, the book may
truthfully be said to present the very latest formulas to be foimd in the arts and industries,
and to retain those processes which long experience has proven worthy of a permanent record.
To present here even a limited number of the subjects which find a place in this valuable work
would be difficult. Suffice to say that in its pages will be foimd matter of intense interest and
immeasurably practical value to the scientinc amateur and to him who wishes to obtain a
knowledge of the many processes used in the arts, trades and manufacture, a knowledge
which will render his pursuits more instructive and remunerative. Serving as a
reference book to the small and large manufacturer and supplsring intelligent seekers with the
information necessary to conduct a process, the work will be found of inestimable worth to
the Metallurgist, the Photographer, tiie Perfumer, the Painter, the Manufacturer of Glues,
Pastes, Cements, and Mucilages, the Compounder of Alloys, the Oook, the Physician, the
Druggist, the Electrician, the Brewer, the Engineer, the Foundryman, the Machinist, the
Potter, the Tanner, the Confectioner, the Chiropodist, the Manicurist, the Manufacturer of
Chemical Novelties and Toilet Preparations, the Dyer, the Electr<^later, the Enameler, the
Engraver, the Provisioner, the Glass Worker, the Goldbeater, the Watchmaker, the Jeweler,
the Hat Maker, the Ink Manufacturer, the Optician, the Farmer, the Dairynian, the Paper
Maker, the Wood and Metal Worker, the Chandler and Soap Maker, the Veterinary Surgeon,
and the Technologist in general.

A mine of information, and up-to-date in eveiy respect. A book which will prove of value
to EVERYONE, as it covers every branch of the Useful Arts. Every home needs this book;
every office, every factory, every store, every public and private enterprise — ^EVERYWHERE
—should have a copy. 800 pages. Price $3«00

WHAT IS SAID OF THIS BOOK:

"Your Twentieth Century Book of Recipes, Formulas, and Processes duly received. I am
glad to have a copy of it, and if I could not replace it, money couldn't buy it. It is the best
thing of the sort I ever saw." (Signed) M. K. Tbux, Sparta, Wis.

"There are few persons who would not be able to find in the book some single formula that
would repay several times the cost of the book." — Merchants* Record and Show Window.

^ I purchased your book, * Henley's Twentieth Century Book of Recipes, Formulas and Proc-
esses,' about a year ago and it is worth its weight in gold." — ^Wm. H. Mubrat, Bennington, Vt.

"ONE OF THE WORLD'S MOST USEFUL BOOKS"

**Some time ago I got one of your 'Twentieth Century Books of Formulas,' and have made
my living from it ever since. I am alone since my husband's death with two small childr«[i
to care for and am trying so hard to support them. I have customers who take from me
Toilet Articles I put up, following directionsgiven in the book, and I have foimd everyone ol
them to be fine." — ^Mbs. J. H. McMaksm, West Toledo, Ohio.

so THE NORMAN W. HENLEY PUBLISHING CO.

This book ejvra fuJI dotnils on hU pninis, Irmtinit 'ti a uinciBe and simple mimiuc the fl«s«iU
of neatly everyihing il in ncci^s^y lo uddfraland for a commenwincEt in any braBch of Iba
Indm ilubbEt Mangtn.^lun:, Tlie nmltinK of Bli kindo o[ Rubber Hand SlamoB, arMllArtitla
of India Rubber, I'. H. Cloynrnment Compifflition, Dating Hand BurnipB, the Manipulitioinf
Sheet Ruhber, Toy liallouiui. Indin Rublitr SolutiDDB. CemenU, Blaekinm, Henovatiie.
Varniflh. and Treatiiitnt for India Rubber Shoos, etc.; the Hcklograph Stamp Inks, and Mir
ccllBneouB Not™, with a Short Account of the Discoireiy, Collection and Manuiactiirp of IcdU
Rubber, aro Kt forth in a manner de«ened to bo rtadily underelood, the eiploustiono twins
plain ond simple. Ineluding a efaaptEr on Rubber Tiie Making and VuleaniiiUE; atui •

175 pages, Lluatrated .' flM

^^^S^.

Xd Eiitiift"

Saw Filing and Management of Saws. By Robert GRmaaAw.

on filing, Eumndns, awaking, hammering, and the brajsing of heM
l11 kinds and eives many usefiu hiula and rules for gtimmiH-
jBvlaed and Ealu^. lUusCrated, Ptice flj|

STEAM ENGINEERING

Amertcan Stattonary BnglneerinE. By W. E. Chame.

This book begins at tlis Ixiiler room and takes in the whole nowci plant. AjJain talkgn

tiflB or mathenutticat. All formulas are in simple form 90 that any one undeistanding plua
ArithiuetiD can readdy understand any of them. The author has made this the most ptaaLicM
book in print: haa given the results of his yeara of eiperience. and has ineludod about all tbit
bu to do »ith an eneine room or a power plant. You sje not left to gueas at a single point.
You are shown clearly what to eipect under the variouB oonditiona; how to secure the Im(
results; ways of preventing "shut downa" and repairs; in short, all that goes to make un On
ncpjirements of a good engineer, capable of takuig chsr^ of a plant. It's plain enou^ (or
nraeticai men and yet of value to those high in the profesomn.
X partial list of contents is: The bailer room, cleaning boilers, firing, feeding; pumps, iuper-

pile driving: engines, slow and high speed; vslves; v^ve setting;^ Corliss engines, ■eltioe

....r«.a;nile --,-.- - _,

vers; water needed; lining up; pounda; pins not square in crnsBhead or crank; enginess
tocjs; pistons and piston rings; bearing metal; hardened copper; drip pipea front cylinas
jacket; belts, how made, care of; oils; greases; tesling lubricants; rules and tAhles, ■><■

amir^tionTor a'Ucu^e,'"eto.?ctc 3r^ ^it^ii. £iS pages, illustrated. ' Price .... ftM

Engine Runner's Catechism. By Robert Grimshaw.

ir_ the Btationary engint

t, ErectiDg and Starting, Valve Betting, Care and U
-- 'IpeciJB-----

I£o£t!a^ppi^aMf'ne(Sving Foondr
Use, Emorgeneies. Erecting and H-

lut the catechism are plai

Age as to be readily under

-date; and they are wri
formuto. The work b

1. and profusely illustrate

_ ohism will be of iireat vi

preparing to go forward to b
■■DBnil^ it. will be of no littli

¥he quitiona asked thL_„ ,- - .. ,-

are given in such simple language as to be readily understood by anyone. All tb
^ven are oomplete and up-to5ate: and they are written in a popular style.

- ^ ^. ^ handy siie for the poi^et. d<

CATALOGUE OF GOOD, PRACTICAL BOOKS 31

dern Steam Engineering In Theory and Practice. By Gardner D.
Hiscox.

This is a complete and practical work issued for Stationary Engineers and Firemen, dealing
with the care and management of boilers, engines, pumps, superheated steam, refrigerating
machinery, dynamos, motors, elevators, air compressors, and all other branches with which
the modern engineer must be familiar. Nearly 200 questions with their answers on steam
and electrical engineering, likely to be asked by the Examining Board, are included.
Among the chapters are: Historical: steam and its properties; appliances for the generation
of steam; types of boilers; chimney and its work; heat economy of the feed water; steam
pumps and their work; incrustation and its work; steam above atmospheric pressure; .flow
of steam from nozzles; superheated steam and its work; adiabatic expansion of steam; indi-
cator and its work; steam engine proportions; slide valve engines ana valve motion; Corliss
engine and its valve gear; compouna engine and its theory; triple and multiple expansion
engine; steam turbine; refrigeration; elevators and their management; cost of power; steam
engine troubles; electric power and electric plants. 487 pages, 405 engravings. 3rd Edition.
Price 13.00

am Engine Cateeliism. By Robert Grimshaw.

This unique volume of 413 pages is not only a catechism on the question and answer principle
but it contains formulas and worked-out answers for all the Steam problems that appertain to
operation and management of the Steam Engine. Illustrations of various valves and valve
gear with their principles of operation are given. Thirty-four Tables that are indispensable
to every engineer and fireman that wishes to be progressive and is ambitious to become master
of his calling are within its pages. It is a most valuable instructor in the service of Steam
Engineering. Leading engineers have recommended it as a valuable educator for the begin-
ner as well as a reference book for the engineer. It is thoroughly indexed for every detail.
Every essential question on the Steam Engine with its answer is contained in this valuable
work. 16th Edition. Price $!3.00

am Engineer's Aritlimetie. By Colyin-Chenet.

A practical pocket-book for the steam engineer. Shows how to work the problems of the
engine room and shows "why." Tells how to figure horsepower of en^nes and boilers; area
of boilers; has tables of areas and circumferences; steam tables; has a dictionary of engineering
terms. Puts you on to all of the little kinks in figuring whatever there is to figure around a
power plant. Tells you about the heat unit; alMolute zero; adiabatic expansion; duty of
engines; factor of safety; and a thousand and one other thinra; and everything is plain and
simple — ^not the hardest way to figure, but the easiest. 2nd Edition. Price . • 50 CentS

sine Tests and Bofler Effldendes. By J. BucHETn.

This work fully describes and illustrates the method of testing the power^ of steam engines*
turbines and explosive motors. The properties of steam and the evaporative power of fuels.
Combustion of fuel and chimney draft; with formulas e3q>lained or practiciuly computed.
255 pages, 179 illustrationfl. Price |3.00

rsepower Cliart.

Shows the, horsepower of any stationary engine without calculation. No matter what the
cylinder diameter of stroke, the steam pressure of cut-off, the revolutions, or whether con-
densing or non-condensing, it's all there. Easy to use, accurate, and saves time and calcula-
tions. Especially useful to engineers and designers. Price 50 CentS

STEAM HEATING AND VENTILATION

icticai Steam, Hot-Water Heating and YentQation. By A. G. Einq.

This book is the standard and latest work published on the subject and has been prepared for
the use of all engaged in the business of steam, hot-water heating, and ventilation. It is an
original and exhaustive work. Tells how to get heating contracts, how to install heating and
ventilating apparatus, the best business methods to be used, with "Tricks of the Trade" for
shop use. ^ Rules and data for estimating radiation and cost and such tables and information
as make it an indispensable work for everyone interested in steam, hot-water heating, and
ventilation. It describes all the principal systems of steam, hot-water, vacuum, vapor, and
vacuum-vapor heating, together with tne new accelerated systems of hot-water circulation,
including chapters on up-to-date methods of ventilation and the fan or blower system of heat-
ing and ventilation. Containing chapters on: I. Introduction. II. Heat. III. Evolution
of artificial heating apparatus. IV. Boiler surface and settings. V. The chimney flue.
VI. Pipe and fittings. Vll. Valves, various kinds. VIII. Forms of radiating wtcI^am^. \?

THE NORMAN W. HENLEY PUBLISHING CO.

^^^^^^S of radiating surfaces. X. Estimating radiation. XI. Steam-heating appantoii
i, ^^<^ust-8team heating. XIII. Hot-water heating. XIV. Pressure systems of hot^irafter
work. ' XV. Hot-water apmiances. XVI. Greenhouse heating. XVII. Vacuum vapor aai
J^cuum exhaust heating. XVIII. Miscellaneous beating. XIX. Radiator and pipe cooiwe^
uons. XX. Ventilation. XXI. Mechanical ventilation and hot-blast heatmg. XXIL
Steam appUances. XXIII. District heating. XXIV. Pipe and boUer covering. XXV. Teai-
(^i^ture regulation and heat control. XXVI. Business methods. XXVII. Miscellaneoai.
^IrYm* Hules, tables, and useful information. 367 pages, 300 detailed engravings. 2nd
Edition— Revised. Price ^M

FiTe Hundred Platn Answers to Direct Questions on Steam, Hot-Water,
Vapor and Yaeuum Heating Practice. By Alfred G. King.

This work, ]iist off the press, is arranged in question and answer form; it is intended ass
guide and text-book for the younger, inexperienced fitter and as a reference book for all
fitters. This book tells "how" and also tells "why". No work of its kind has ever beet
published. It answers all the questions regarding each method or system that would be
asked by the steam fitter or heating contractor, and may be used as a text or reference book,
and for examination questions by Trade Schools or Steam Fitters' Associations. Rules, data|
tables and descriptive methods are given, together with much other detailed informatifm of I
daily practical use to those engagedin or interested in the various methods of heating. Val-
uable to those preparing^ for examinations. Answers every question asked relatingto modem
Steam, Hot-Water, Vapor and Vacuum Heating. Among the contents are: The Theoiy and
Laws of Heat. Methods of Heating. Chinmeys and Flues. Boilers for Heating. Boiler
Trimmings and Settings. Radiation. Steam Heating. Boiler, Radiator and Pipe Connee>
tions for Steam Heating. Hot Water Heating. The Two-Pipe Gravity System of Hot Water
Heating. The CircuitSystem of Hot Water Heating. The Overhead System of Hot Water
Heating. Boiler, Radiator and Pipe Ck>nnections for Gravity Ss^tems of Hot Water Hea^
ing. Accelerated Hot Water Heatiiu;. Expansion Tank CJonnections. Domectic Hot Water
Heating. Valves and Air Valves, vacuum Vapor and Vacuo-Vapor Heating. Mechanieal
Systems of Vacuum Heating. Non-Mechanical Vacuum Systems. Vapor Systems. Atmoa*
pheric and Modulating Systems. Heating Greenhouses. Information, Rules and TabkBi
200 pages, 127 illustrations. Octavo. Cloth. Price $l«fil

STEEL

Steeir Its Selection, Annealing, Hardening, and Tempering. By E. R.

Mareham.

This work was formerly known as "The American Steel Worker,** but on the publicstioi
of the new, revised edition, the publishers deemed it advisable to change its title to a molt
suitable one. It is the standard work on Hardening, Tempering, and Annealing Steel of all Idodb
This book tells how to select, and how to work, temper, harden, and anneal steel for everf
thing on earth. It doesn't tell how to temper one class of tools and then leave the treatmeat
of another kind of tool to your imagination and judgment, but it gives careful instructitfM
for every detail of every tool, whether it be a tap, a reamer or just a screw-driver. It teBj
about the tempering of smaU watch springs, the hardening of cutlery, and the annBalin^ of
dies. In fact, there isn't a thing that a steel worker would want to know that isn't inchioed.
It is the standard book on selecting, hardening and tempering all grades of^ steel. Amoof
the chapter headings might be mentioned the following subjects: Introduction; the wo
man; steel; methods of heating; heating tool steel; forging; annealing; hardening bat
baths for hardening; hardening steel; drawing the temper after hardening; exampla^
hardening; pack haidening; case hardening; spring tempering; making tools of ma "
steel; special steels; steel for various tools; causes of trouble; high-speed steels, etc.
pages. Very fully illustrated. Fourth edition. Price fSi

Hardening, Tempering, Annealing, and Forging of Ste^. By J. V. Wood-
worth.

A new work treating in a clear, concise manner all modem processes for the heating, uinea^
ing, forginff, welding, hardening and tempering of steel, making it a book of great pracow
value to the metal-working mechanic in general, with special directions for the succe MTW
hardening and tempering of all steel tools u^d in the arts, including milling cutters, tape, threat
dies, reamers, both solid and shell, hollow mills, punches and dies, and all kinds of ehw^
metal working tools, shear blades, saws, fine cutlery, and metal-cutting tools of all deeoV"
tion, as well as for all implements of steel both large and small. In ^is work the simpleM
and most Batisfactory haruening and tempering processes are given. ^ ^

The uses to which tne loading brands of steel may be adapted are concisely presented, aai
their treatment for working under different conditions explained, also the special metbodl
for the hardening and temporing of sjjecial brands.

A chapter devoted to the different processes for case-hardening is also included, and
reference made to the adaptation of machine^ steel for tools of various kinds. Foi
tion. 288 pages. 201 illustrations. Price

tr^

CATALOGUE OF GOOD, PRACTICAL BOOKS 33

TBACTOBS

The Modern Gas Tractor. By Victor W. Taq±, M.E.

A complete treatise describing all types and sises of gasoline, kerosene and oil tractors. Con-
siders design and construction exhaustively, gives complete instructions for care, operation
and repair, outlines all practical applications on the road and in the field. The best and
latest work on farm tractors and tractor power plants. A work needed by farmers, students,
blacksmiths, mechanics, salesmen, implement dealers, designers, and engineers. Second edition,
revised and enlarged. 504 pages. Nearly 300 illustrations and folding plates. Price ^.00

TXJBBINES

Marine Steam Turbines. By Dr. G. Bauer and O. Lasche. Assisted by
E. Ludwig and H. Vogel.

Translated from the German and edited by M. G. S. Swallow. The book is essentially prac-
tical and discusses turbines in which the full expansion of steam passes through a number
of separate turbines arranged for driving two or more shafts, as in^ the Parsons system, and
turbines in which the complete expansion of steam from inlet to exhaust pressure occurs in
a turbine on one shaft, as in the case of the Curtis machines. It will enable a designer to
carry out all the ordinary calculation necessary for the construction of steam turbines, hence
it fills a want which is hardly met by larger and more theoretical works. Numerous tables,
curves and diagrams will be found, which explain with remarkable lucidity the reason why
turbine blades are designed as they are, the course which steam takes through turbines of
various types, the thermodsmamics of steam turbine calculation, the infiuence of vacuum
on steam consumption of steam turbines, etc. In a word, the very information which a de-
signer and builder of steam turbines most requires. Large octavo, 214 pages. Fully illustrated
and containing eighteen, tables, including an entropy chart. Price, net S3 .59

WATCH making'

Watchmaker's Handbook. By Clauditts Saunier.

No work issued can compare with this book for clearness and completeness. It contains
498 pages and is intended as a workshop companion for those engaged in watch-making and
allied mechanical arts. Nearly 250 en^avings and fourteen plates are included. This is
the standard work on watch-making. Price $3*00

WELDING

Automobile Welding with the Oxy-Acetylene Flame. By M. Keith Dunham.

Explains in a simple manner apparatus to be used, its care, and how to construct necessary
shop equipment. Proceeds then to the actual welding of all automobile parts, in a manner
understandable by every one. Gives principles never to be forgotten. Aluminum, cast iron,
steel, copper, brass, bronze, and malleable iron are fully treated, as well as a clear explana-
tion of the proper manner to burn the carbon out of the combustion head. This book is of
utmost value, since the perplexing problems arising when rietal is heated to a melting point
are fully explained and the proper methods to overcome tLem shown. 167 pages, fully illus-
trated. Price $1.00

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Full text of "The A-B-C of aviation; a complete, practical treatise outlining clearly the elements of aeronautical engineering, with special reference to simplified explanations of the theory of flight, aerodynamics and basic principles underlying the action of balloons and airplanes of all types"

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